A little tip from a former residential tech, replace all 370 vac capacitors with 440 vac capacitors using the correct microfarad rating. IE: 35/5 mfd. 370vac dual capacitor fails, replace it with a 35/5 mfd 440vac capacitor. I can't ever remember having a callback on the same unit for a repeat failure in 9 years of service. Good luck guys!
@@rodeoclownobama5796 lol, you sound like the uhaul tech who told me I was going to "over juice" ...his exact words.... and burn out my trailer lights by using a larger diameter wire...as if somehow magically the trailer lights will use a dangerously high amount of electricity just because the conductor is larger.
I'm a former instructor, still running service...This is an excellent video...Better than most, clear, easy to understand, and well done....Thanks again for what you're doing.
Can you tell me this, please. Is the capacitor an all-or-nothing type device, meaning, if it’s good, it’s good, and if it’s not, it’s dead OR can it become inefficient over time and operate poorly, degrading the efficiency of the A/C and driving up costs?
@@Unknown17 Yes...They can weaken...The Micro Farad rating drops off more so than the voltage...When it happens motors run hot, if at all...They have meters that can check them...10% under...It's bad for the motor...I replace them if not right on the plate rating...Once weak, it will only get weaker.
@@vernroach3413 Thank you! Just had one die on my home unit the other day, which was replaced. Even tho’ I’m a pretty old guy now, there are some holes in my education and life experience, and this is one of them. Oh, I also suck at knowing my flowers and trees. I don’t know an Ash from a hole in the ground, ha-ha. ‘Predicate ya!
@@Unknown17 You're welcome friend...I'm aging out myself, late 70's, now doing favors more than actual service anymore...Helping people save money, keep them from being gouged and the gougers are out there...Still learning, still complaining, and still wondering, what the hell is going on...Be safe.
I am amazed how much knowledge is available on the internet for free from folks willing to share it. Thanks for making these videos. Also, thanks for providing the Amazon links. Looking through them reminded me that I need to get some vacuum pump oil and pick up a swaging tool for an upcoming job.
I agree. I managed to install my minisplit completely on my own. Aside from wiring the outdoor unit up to the mains power, as that was done when my entire tiny home was wired.
@@JediOfTheRepublic Actually, that is not my experience. In 1989 I went to several libraries looking for books on sizing and installing central AC in a residential home. I had bought my first house and wanted to install central AC. I went to the largest regional library in northern Ohio, to the branch noted for science and technology materials. I went to the Cleveland Public library main branch (two large buildings, 8 floors). At the time it was reputed to be the largest library in Ohio. Neither library had the type of book I needed. They did have a book suitable for engineering students that required calculus, but not the practical info one would need to install central AC. When I asked the librarian why they did not have such a book, she said that it was probably too complicated for most people. Now, we have high school drop outs in the HVAC trade, so I know it isn't rocket science. I ended up finding a text book on the internet (this was pre-YT, and in the days of dial up) that was intended for trade school students. It covered car AC, residential, commercial, etc. from beginning to end, hardcover and about 3" thick.
@@BryanTorok If you look at my channel, I got crud quality vidoes too, you can see my install, but I'm disabled, and it would look like crud. The guy I hired, does clean professional work. I have the industrial look with exposed conduit everywhere. I'll make repairs, do outlets, ceiling fans, etc. But not a full install with conduit bending, etc. Guy did it over 2 days in 110 heat, as no ac, as there was no electrical. Would take me like 5 years at my pace and still look like crud.
I honestly can't even remotely consider why anyone would thumbs down this video... It is distinctly, one of the absolute best explanations on YT for value, reason and explaining the math behind it. Job well done Sir.
simple to explain why the thumbs down - it is u -tubes fault. if you give a thumbs up you will get blasted with stuff similar to . since i just was interested and not wanting more similar, thumbs down - NOT because its a bad video. stupid the way utube does things.
Probably down voted by an AC guy that don't want people to know how easy and inexpensive it is to replace! He loses business over these types of videos. Emergency call, service, and part $450.00 for something that can be fixed in 10 minutes and the cap is under $20.00.
When I was a kid the capacitors lasted the entire life of the unit. I've seen caps so old the only reason they had to be replaced was because the 25 year old terminals had rusted through and you couldn't get a connection on them anymore. Those caps were oil filled and weighed a couple pounds. They were also a lot bigger in physical dimensions, a 30mfd was about 7 inches long oval can.. The caps we have now sometimes fail in a year and feel like they're filled with air.
@@agsession7664 Depends on what is made too...I do believe Sony is from Taiwan...Far better than China...South Korea for the most part, good products...Mexico, depends on what it is...Most receivers will last for years, no matter who made them...It's just a receiver...They're not under the stress some products are.
@@curtishuzarewich7033 I think it was actually because they were foil caps, not vacuum deposited metal films on plastic film. Could handle current overloads without overheating. IMO. Mr KL
Thanks. I had a string of cap failures on a new Trane sysyem. After the first 3 or 4, the AC guy measured voltage. I had a bad street transformer and 1 leg was 115, the other leg was 132. Town came and replaced it, no problems ever since.
I always keep a spare capacitor at home. After the first $250 bill for replacement, I learned to do it myself.. Only a $20 part so cheap to keep a spare. In Texas they are the most common failed part on a home AC and they charge an arm and a leg to come and replace it. Literally takes 5 mins to replace..Easy to test with a volt meter..
Yeah, Texas is hot. And they aren’t failing a lot. I’ve only replaced 2 in 10 years. But there so cheap, why not have one on hand instead of paying a high prices service charge and having to be without AC overnight or more than 8 hours in 110 degree weather while you wait for that service call…
I have spare capacitors and replace it as a planned-maintenance item (PMS in the Navy as an ET is planned maintenance system, fix it to keep it working when you never know when SHTF).
For anybody wondering where the numbers come from, recall that impedance of a cap is 1/(2*pi*f*C). Plug that impedance into Ohm's law and rearrange to get C by itself, and assume 60 Hz. Dynamic testing like this will be much more accurate in a real world situation. Brilliant video!
@ spelunkerd anyone NOT anybody One is the Cardinal Number One is alive One is unique There has NEVER been one like you in existence before you were born There will never be one like you after you die You only have 'one' soul - thus you are 'one' Every body is the same : Rotten and stinking after four days 'Body' refers to a DEAD ENTITY. You will find every'body' in the cemetery. Unfortunate your education system is pathetic and 3rd world standard - designed to manufacture ignorance and dumb down the population The reason why Latin is not taught in school these days is so that people do not understand the origin or the real meaning of the words they use. Had you been a student in my English and History classes you would have a better grip and knowledge of the English language - and North Americans are among the least educated of all the OECD countries- scoring at the bottom end - where 1 is the highest - 50 is the lowest. The US is not even in the top 30 of the best educated.
@@f.hababorbitz Remember it's in the denominator, so you need to invert the number, 1/377= 0.002652. Then note that for simplicity he changed units to get rid of micro units by multiplying by 1,000,000.
I’m a Contractor now but been in the HVAC trade for 18 years and I still learn from your videos, good stuff and some of it I’ve forgotten about. Thanks for putting in the effort!
On high end heat pumps a soft starter is used instead of Start and Run capacitors. But if manufacturers of lower end units fix the problem of capacitors always failing then a ton of service technicians would have very little to do.
Craig, you have a natural talent for explanation and always demonstrate these concepts. I'm a visual learner and appreciate it. The Mini Split book is one of a kind! We didn't get much time to chat, but I hope to see you next year at the HVAC Symposium in Clearmont!
Thank you for the great content! Having a clamp ammeter plus a good DVM makes checking the capacitance very easy as opposed to cutting the power, discharging the caps, disconnecting the caps and using a meter that can measure capacitance. I also like the fact that your way tests the cap under load. With the supply chain woes I think I'll buy an extra just in case. Everything in your A/C system is designed to fail after closing time on Friday in August.
I love your closing comment. Isn't it the truth. I'm not an HVAC guy but I maintain a surplus of new and salvaged items around the house in those emergency situations.
HVAC school was insisting caps fail due to overvoltage (transient / surge). When I suggested it was heat, I was essentially told I was stupid. I've had really good luck replacing with two capacitors to spread the heat load. I also agree with the commenter who suggests caps with higher voltage ratings. Everything I've seen suggests heat is the real culprit.
An apt. complex installed all condensers on roof, shingles. The heat destroys them in 2 years, a rotating problem. They decided to put all 114 of them back on ground. No more fails.
@@danielabilez3619 It is heat. I am EE trained and HVAC tech. Try placing Condensers on roof with lineset and watch the failure rate skyrocket. Recommend the 440 VAC rated.
yep, but excessive current through(strictly in and out, a cap shouldnt pass current through it directly) and/or overvoltage can cause internal heating as well, eventually destroying it , some motor caps are rated for intermittent start use only not 'run' .. you have to use the correct type
Thank you, your video is by far the best at explaining why capacitors fail. When I built my house I purposely placed the AC unit on the north side of my house away from the sun. Not only does it help save capacitors it also lets the unit run more efficiently.
I see several comments that share my thoughts here: A. Excellent delivery of information. No unnecessary pauses nor tangents, you stay on point and you are very concise. You ought to teach HVAC/Electrical if you don't already. I am very impressed. Oh, and you answered my questions. I had no idea what dielectric fluid was before today and that explains the size and shape of transformers on telephone/electric poles. Pure physics inside a capacitor...surface area for storing electrons. Color me schooled. Though I'm now more curious than ever.
Excellent video. I replaced my 20 year old 30/3 MFD capacitor after condenser fan would not start (but would with a push). Cleaned all connections and replaced capacitor. Old one measured 29.8/4.7, indicating a leaky capacitor on fan side. New one measured well within 1% of spec. I also measured total amps to condenser unit before vs. after repair which dropped from 8.9 to 8.15. System runs great now.
Hands down this is the best video I have found on youtube for this topic. The guy didn't go to deep but just deep enough to give enough of the math behind what was going on to arm a DIY'er with with what they need to understand when replacing these caps themselves (or at least dealing with an AC contractor.)
Wow. Excellent presentation on capacitors. I have two 3 ton AC systems at my house. Last week one capacitor failed. AC service tech fixed it and 3 hours later after he left the second one failed on other unit. I remember looking at it and it looked bulged on the top and "wet". But tech didn't realize as far as I can tell now what the telltale signs were that it was bad our about to go bad. My take away from this experience is that after a $308 service call I need to buy spare capacitors. Which I have now done at a whopping $16.80 each. These should be treated light light bulbs and every homeowner should have a spare on hand. If AC won't start it's super simple to swap out cap. There is an 80% chance that is the problem and you are back up and running right away without having to call for expensive service.
If you don’t mind me asking, where do you buy these spare capacitors? After watching this video I had the same thought of having a spare as a lot of times that is why a system goes down.....thanks
@@sktoh4469 yes. if the capacitor is charged you do not want to short your self across it. The standard technique for handling capacitors especially "power capacitors" is to ensure that you short the terminals to dissipate any charge. Easily done by placing a good conductor across it like a screwdriver shaft.
Finally! In my 48 years of HVAC I witness someone who knows what he is talking about. Heat and life, I have argued, are the only two culprits of failed capacitors. Cheap manufacturing is a culprit, but only because the cheap caps can't take the heat. I use only USA made caps in 440v. I have had repeated failures on a few condensers, and after moving the cap to the inside of the condensing coil where the fans air movement can cool the cap off, the failures quit. By doing what RUUD/Weatherking has done by making a hole in the cabinet and slipping the cap into the airflow. *You'll need to make sure the leads aren't exposed to the weather. Job well done.!!! Oh! Just one more thing, though it is tedious- "2652" is more accurate for me. A long time discussion I'm sure you have had.
Heat reduces the life of any component. If the manufacturer wanted to do something about that, they easily could. There's a giant fan in the condenser... How about putting a couple of vents in the electronic compartment so there's a bit of airflow from the fan?
What I saw regarding the voltage measurements reminded me of something I first read as a military guideline for component reliability. I was surprised, but the saw other supporting information, including and especially the Arrhenius studies of temperature effects. Anyway, what I then decided to make my permanent memory, is that you never use the components at the listed ratings! You design your systems to stress the components only to 70% voltage and 70% current relative to the manufacturer listings. In other words, consider the listed values as maximum, not as safe continuous ones. In the shown case, the 365 V appearing on the capacitor would require 550 V or 600 V rated capacitors. That assuming the manufacturer would not cheat and label their capacitor higher voltage, knowing that the users will do the derating...
@@bryanhauschild4376 Yes - that is what I saw on on the meter display in the video. If that sounds wrong, just think what happens when you have an inductive coil (motor) and the capacitor in series. Depending on the two values, there is a resonance at some frequency, maybe a harmonic of the line frequency. In resonance or even near a resonance, you get an increase in voltage over EACH component. In theory (infinite Q, zero resistance), the voltage would climb to infinity. In practical situation, the circuit Q is not infinite, but some over voltage is developed anyway.
@@bryanhauschild4376 Hey Bryan. Resonance is where the inductive reactance, XL and capacitive reactance, XC are equal to each other. At this point, the voltage across the inductor and capacitor are equal, but the voltages are 180 degrees out of phase. This will create minimum impedance in the circuit where the current is the highest which is only limited by the resistance of the winding. This pertains to a series circuit where the inductor start winding and run capacitor are in series. It has nothing to do with sound.
here in the US southeast im seeing alot of capacitors fail within the warranty of the unit, ive noticed that these capacitors are made by the same company, we replace them with a cap made by a different company from a different place and they last significantly longer for some reason
EXCELLENT video! As mentioned by @classic Pontiac37, sometimes using a higher voltage rated cap will make things last longer. In petrochem control systems, I've seen blown out power supply filter capacitors that the manufacturer pinched pennies on and were within a volt or 2 of the running voltage. Running "rated voltage" that close is not good in HVAC or in production plants running 24/7. We solved that problem by replacing all of those "too tight" VDC filter capacitors with ones almost triple the running voltage. No more failures.
Thanks for the video! My HVAC capacitor recently failed and due to the recent heat wave and we could not get a vendor out. Was able to get a capacitor and install it with the help of videos like yours (locked out the circuit, waited, then tested for residual voltage). the old capacitor had good shape but the top was wet from electrolyte leaking. Thanks!
He heated the capacitor at the bottom. It wasn't made very clear in the narration. I saw many comments asking this, and after seeing several comments that he did actually mentioned this, I replayed the video until I found it mentioned vaguely at 5:42. I assume he heated it with a torch... Good demonstration! Fun to see the disconnect feature in action. Thank you! It would be very interesting to repeat this with a thermocouple reading the case temperature at the moment of failure... It likely exceeded the lifetime max temp rating, but that is how accelerated life tests are usually done anyway. I don't know if you are inclined to try this again. Maybe extend the leads and place it in an enclosure that you can heat evenly and gradually, until it fails? At the minimum, we would learn how much 'headroom' we have above 160ºF, and when 'lifetime' becomes '0' hours... Mr KL
Our made in China capacitor failed in our Goodman unit at 6 years. The salesman at WW Grainger said 5 years is usually max life. New Dayton replacement is also made in China for $ 38. I bought 2. 1 for a back up for the future. Thank you for the great video, and informative comments from electronic geniuses.
All electrolytic capacitors have a limited lifespan, don't let any snake oil salesman tell you otherwise. It doesn't matter where it's made, it will fail eventually, physics doesn't care about nationality, buy quality caps from manufacturers with a track record.
@@Nomorage China can and does make any component classification ranging the entire quality spectrum. They are the #1 country for receipt of the rest of the world's outsourcing needs. If you want premiere quality just spec it so, they will make. Multi thousand dollar Trek bikes may be assembled in Wisconsin still, but the frames come from giant state of the art Chinese factories now, made to Trek specifications.
For a callout work, we discovered the facility had a 60 Hz ceiling concealed equipment in a 50 Hz mains power source country and over 80% of the units had swollen & bad capacitors. Apparently, they have been having the issues for a couple of years since commissioning. Once they are changed, the units work just fine. Recommended all capacitors to be changed with the scheduled routine maintenance to prevent downtime.
Excellent video. I have told customers for years the biggest killer of capacitors is heat (I'm in Florida) and the fact that many service techs don't check them to see if they are getting weak. When i was younger it seemed more common for people to have their systems checked/serviced/maintained in the spring as a preventative measure, now they wait until the system breaks down.
Don't you think it is silly or a crime for a person to have a repair person come by to check their system every spring? Old ladies and old men having some unknown dude come into their home to rob them when they come in to use the bathroom? Let alone come up with a bogus replacement and never offering to even show them the defective part. Why don't they build them right in the first place. Solar panels last 25 years and you don't need a yearly service call. The days of constant repairs and checks are over hopefully.
@@AvgDan My comment was about the idea of having a service technician come into your home and verifying the unit will work for the next season. I'm not talking solid state or HVAC but just the idea that you have to allow a person into your house every season to check us out. Even so there is no real guaranties. You can do a preseason check and it can still fail.
Thank you. My AC broke down in 113F (and climbing) weather and my multi-meter doesn't read capacitance. The formula you mentioned saved me from buying another multi-meter. The way you explained the causes of failure is amazing.
I have seen a catastrophic failure of a cap from a lightning strike. It was the start cap for a deep well motor. It literally blew the top of the cap off ,which caused it to blow off the top of the control box. All that was left was the metal can and a spiral of the electrodes and dielectric material hanging out of the box. As a rule of thumb for me I always replace the starting caps on equipment over ten years old.
@@GonzoDonzo Seems like incredibly poor design, especially when it can be prevented. Is there a particular reason that contractors put with this failure mode for so long? An incentive, of some sort? Perhaps?
@@exgenica the old capacitors filled with nasty oils that were many times larger, rarely failed. Contractors dont have a choice. U can buy better quality but they still fail. They are like the old incandescent light bulbs. It should last for years but sometimes they burn out a week after u screwed it in. Generally its indicative of something else going on as well but its the weak link in the chain and will go first
@@GonzoDonzo said, "Contractors dont have a choice." Contractors have the power of unions, professional organizations, conventions, and even individual feedback to motivate the manufacturers to reduce these field problems in future A/C designs. Those that haven't provided that feedback to any organizations they belong to and to the manufacturers...have some responsibility in the problem still being as big as it is.
The best replace ac capacitor video. I had money go put 3 years ago and didn't know anything about. A friend on a phone fall told me likely the capacitor. While the a/c man was fixing I told him ot was the capacitor and he confirmed. Charged me 430.00 to replace A $15 part that I could have replaced just as easy. Expensive lesson learned.
It is interesting that in 2022 nobody has invented a capacitor or replacement device/component that lasts 5x longer or even not burn out. Nice video - impressive.
Whenever I replace a dead cap on a relatively new unit I always get one with a higher voltage rating if possible (30-40%). Inductive kick always exceeds the rating but because it's very brief it takes time to damage the dielectric material.
2022? This should have been done decades ago. Connector design, enhanced cooling, properly spec'd voltage, unit failure chemicals containment...the whole bit should have been properly designed a LONG time ago. Putting up with all those separate failure modes for decade after decade seems very hard to justify.
@@wiregold8930 At my place of work (rewind shop) we've noticed that the 400 VAC run caps (on 240 V. motors) don't last anywhere near as long as same rated 450 VAC run caps. Also, If any cap measures lower than rated capacitance, you can guarantee it's on the way out.
In high heat (70C) or high voltage breakdown, it is the polypropylene that melts. When it partly melts it creates a weak spot that has a lower withstand voltage, letting it get even hotter.
6:36 "If this shield is in the sun all the timer" or if an A/C repairman is holding a torch to the bottom of the cap, it's gonna blow! I gotta say, the wealth of information you shared just then was outstanding, not something you see everyday. Thanks!
Took my first cap apart in the late 70's - was amazed. A friend called me one time in the early 80's ... got an estimate of $650 to replace a compressor. Cost $5.49 for a cap. Moved into my house in 88. Replaced the cap every 5 years for quite a while. Went from the oval shaped unit to a round one (Oval - out of stock) Round one still running after 10 years on my 40-year-old unit. Maybe I need to move the cap to the evap line. Very good presentation -Thanks
@@randyosborn284 Was that PCB? I used to smell a small from Fluorescent Lighting ballasts in the 70's 80's and early 90's that I assumed were PCB's, but wasn't sure, the caps In my AC unit were pretty tame. I got a feeling it is some other hideous noxious oil now. Maybe not. It did have some kind of vinal smell though
EXCELLENT video. To the point minus fluff - WELL DONE. In my working days, I spent 17 years as a A/C tech. I also am a electronics tech and have been for decades. I did NOT know that formula. NEVER heard of it. I see it is ohms law with the 2650 number added in. Curious as to where YOU learned of it. You can bet I will NOT forget it. Also, 100% agree that replacement capacitors should be rated 400+ volts - ALWAYS. This is especially true in the desert southwest where I am. Here, I also used ONLY desert rated ball bearing fan motors. It MATTERS.
This 2650 stumped me for awhile too and it is really 2654 not 2650, but close enough. Here is where it comes from. V=I x Xc (capacitive reactance) and Xc=1/(2*pi*f*C) where f is 60 cycles per second. 1/(2*pi*60)= 0.002654 so Xc= 0.002654/C. Therefore C= I*0.002654/V which is a value with many leading zeros (microfarads). To get rid of all of those leading zeros just assume the answer is in microfarads by multiplying the 0.002654 by 10^6 (1,000,000). Hope this makes sense.
I've seen capacitors fail when the "operational smoke" is released. I've also seen this happen to resistors and other electronic components. If a way can be found to make the smoke containment more robust, I believe component life could be maintained indefinitely.
The Magic Smoke is indeed a fickle material in any component it's used in. IBM had replacement smoke they sold, give it a google search. The hard part was getting it back into the part :| Big bucks job there.
I noticed our clocks flashing on appliances. The was a power outage of some kind. After youtubing a bit I ended up using the multimeter and found the capacitor blown. switching out our capacitor worked. We were up and running on a friday evening. I just made it to the supply house that had one with minutes to spare. I watched your video for a better understanding. Thank you for sharing your knowledge with the diy’ers of the world
LOL - I ALWAYS wind up at the last minute by the time I finally learn what I need! The clock is ALWAYS at 15min til closing, no matter HOW much earlier I started the troubleshooting! Mr KL
Re: corrosion. With automotive headlights it used to be pretty much routine to apply an anti-moisture/corrosion material to the connectors. Seems like for decades the A/C industry has (intentionally?) used the wrong design connectors and not properly advised sealing the connections to reduce corrosion.
Plus needing one hand 2 inches wide and the other with 7 fingers to change the headlight bulb from my experience and without touching it also with halogen.
Well it's a good thing that HVAC units aren't driving on roads sprayed with brine in the winter and exposed to all the extreme vibration and other contaminates that motor vehicles are on a daily basis. Obviously the outside condensing unit is stationary, sealed better and therefore shielded from all the nasty things automobile electrical systems are exposed to. Hence the lack of protection seen in mobile applications... yet not always there either due to poor quality manufacturing, cutting corners, and of course the TH-cam graduates who don't have all the facts, tools and materials. But by all means, please do yourself a mental favor by applying heat shrink insulation and dielectric grease to all of your HVAC electrical connections and put a sun shade over it. It is just a heat pump after all.
@@michaeld5888 I've never had much difficulty with headlight bulbs or bulb assemblies. Guess I've been lucky. Thanks for letting me know it can be a problem. However, for "and without touching it also with halogen." When handling halogen bulbs, I use gloves if I absolutely have to touch the glass envelope. If I can't, I try to clean oil contaminants off the bulb as much as possible before I seal it up. Many people don't know that even fingerprints from skin oils can significantly reduce the life of halogen bulbs so that's another good bit of info you've brought forward to people.
@@rjbradlow So...just because there are additional issues in a different environment, you get all sarcastic and mean and *don't even try* to solve even one of the problems? Sounds like a Millenial talking.
Great explanation. I serviced commercial refrigeration and AC for years. I don't have nearly as much experience with capacitors. I gained a lot of understanding from this.
Careful of those Chinese capacitors. I bought one for a motor I was using for a project and it was much lighter then the old one. I used it and it lasted a couple of starts. For giggles I cracked it open and it was a 240volt 5uF X/Y safety cap typically used in ceiling fans crudely soldered to the lugs.
@@paulcopeland9035 The cap I wanted was on back order and I thought the cheap one could hold on until I got the proper one. Wasn't for a A/C or anything like that. It was for a wood turning lathe I built from scrap.
True. Replaced mine a few times, sometimes Geckos were the culprit. The last time I put a universal motor in and had to wire 2 capacitors for it. Worked ok but it failed. Finally called AC guy and he replaced it with a US made larger capacitor. Was a bit expensive but he did say many of these capacitors out there are China ones and this one was warrantied. Had some loud starts and stops for a bit, not sure why but it stopped and no problems.
I just changed that very same 45/5 capacitor on our AC unit. It was open on both sides. And I verified it was open, out of the circuit, using a Fluke capacitor meter. $26 dollars later we are comfy again... Thumbs Up!
I have to interject as I have seen high current burn out hundreds of capacitors over 20 years. More accurately the cause was power loss and internal heating due to high ripple current. The ripple current degrades the capacitor by raising its internal temperature!
Nice video. Old AC tech told me tune ups are a racket....He said corrosion causes leads to have higher resistance and causes the most problems. Just turn off the power..remove every wire / connector you can get to and clean the contact area. Also clean out debris and clean coils. Been doing that every spring and my 27 year old unit is still going strong.
My capacitor failed and was told it was going to cost $220 to repair, but it would be a week to repair. I looked up the capacitor on Amazon, cost $18 and a day later I installed it in 5 minutes. Been working ever since. I did order another, just in case.
My experience is that Chinese made capacitors have very short lives. I've had problems with the capacitors on my pool pump motor. I just bought a made in the USA capacitor, we'll see how long it lasts?
Erik, I just had an A/C tech tell me $330 to replace a capacitor, I showed him I could buy the SAME item from Amazon for $21. He told me his boss forbids him from installing such. Blamed Bidenflation and the need to be profitable.
You could buy 2x 10µF/400V and in parallel of 5µF/800V, also 2x 90µF/400V and in parallel of 45µF/800V and hold all of them in the ground to prevent vibra. That is it.
@@chipdenman863 needing to be profitable IS a huge factor. I could clean my own house for about $1 worth of cleaner or hire a person to do the same job for $60-$100. It's always cheaper to diy. Don't hold this against them. They are highly trained pros that must charge for their time wether or not it makes sense to you.
I have lennox unit from 1979 still running at my house. I've changed every part on the unit except for the compressor and the original 45 MFD run capacitor (separate capacitor for the fan motor and compressor). That 45 MFD capacitor from 1979 is HUGE and still running like a champ! I check it every season. I am of the opinion that ever since capacitors were made smaller and smaller they fail faster than ever. Less surface area to dissipate heat. I know it's more convenient to make them smaller, but I feel it has reduced their lifespan.
In 17 years i only ever replaced 2 of the old style capacitors that were much larger. I know they had some nasty stuff inside them but they were rock solid
I was a power supply design engineer in 1984 when capacitors were blowing up. It is all simple once you know the answer. Our caps had a wire welded to the foil making dissimilar metals. The end seals were epoxy with too much filler. The PCB cleaner was getting past the seal to attack the weld. During high ripple current the caps would fail. I don't know if this is why Sangamo capacitors in GA went out of biz.
In the 80's my a/c blew a capacitor each year. The fault was power spikes and brown outs (oe so I later learned). Replaced a perfectly good Frederich with an incredibly awful Lenox. If I knew then what I knew now.
China is why that company shut down I am betting. Buying 1,000 capacitors for $2 is a massive selling point. And a price US citizens simply will not work for. Without competition, that company would have corrected flaws in their designs and would probably still be in operation today. By the way, exploding capacitors still has not been solved. lol I am no designer, but I am a repair tech. Mosfet failure alone can cause a "runaway" current which can have you cleaning a board of capacitor remnants. Its not very common, but they can still detonate. Most of them simply swell or purge their dielectric. Most exploded caps I come across are found oddly in audio amplifiers' output stage. The caps tend to be placed far too close to the amplifying mosfets. And when people run them under 4 ohm loads or lower, the caps heat up dramatically.
My old PC monitor went black...Because of this video I figured why not look, and found 2 bulging capacitors, soldered in new ones and now have a spare monitor. Thanks!!
I'm an HVAC contractor and I would like to give a warning to some of your viewers about "made is China capacitors" sold online. Being in Az with our excessive heat, I have customers that buy and keep spare capacitors. Unfortunately, when buying online, you frequently don't know what quality you are getting. I have seen customers install low quality capacitors which then fail shortly after and sometimes burn out the windings in the compressor. If you buy capacitors online, be sure you are getting the made in USA brands. They cost 4 or 5 times more, but they do last longer and they are a lot cheaper than a new compressor.....
Don't bring your Chinese hatred in this topic because if you purchase the capacitor from a reputed chinese company it will work just as well as American made but will definitely be cheaper than American one.
@@sunny6630 I have no hatred for anyone or any country. I am a licensed HVAC contractor and I stated my real life experience. For you to accuse me of hatred, you are showing your own ignorance of the facts and unwillingness to face the truth. I mentioned that the American brands do cost significantly more, but they are worth it because of the consequences of using poorly made, cheap parts from China.
As an engineer for 50 years, I've opened a lot of blown capacitors. Dielectric failures primarily, then melted foil due to high current surges, esp vintage caps. However in one case, I had a 900 foot deep well pump replaced at a very high cost for me. Later I discovered the removed capacitor in the control box was the culprit. The rivet holding the terminal was loose. The cap was intermittent. The old pump was fine. Aghhh. However its not good for the motor to eat current without starting. Your video shows someone with a lot of experience. Thumbs up.
Thank you the educational video. We just had a power outage in my area and my hvac just stop working the next day. I called the tech out here and they said many homes are not cooling because of the power outtage. I try to reset it by killing the power for about 20 minutes and turn it back on. No luck. I can trouble shoot hvac in cars and big rigs but hvac in a house is a bit more complicated for me because of the unknown. Theses videos help me out understand and not get electrocuted. Lol.
I just had my capacitor replaced with the AmRad Turbo 200x capacitor. He said that were the best and had a 5 year warranty. American made which I like.
I replaced all my AC capacitors with American made capacitors. That extra $50 you spent to replace all the Capacitors with something quality made will probably save you a service call in the future and extend the life your system. Capacitors rust and deteriorate over time. Replacing them every 5 to 10 years before they fail is definitely a smart idea. Beats calling for desperate service in August with your wife melting and having to pay whatever they want to unless you want to wait a few days...
I will add to Henry's comment and say it was a well done video. Having been trained in electronics, I can share a little bit more. First of all, note that "oil filled capacitors" (as those are considered to be) are going to be the first type of capacitor to fail. It's just the nature of the physics behind the makeup of the product. Whatever the cause for the failure, these types are more susceptible to failure. BUT! You can't get another construction type of capacitor that will produce that much capacitance in that size of a package either. They become much larger to match the same capacity. Also they are a very cost savings capacitor as well compared to other construction types of capacitors. These types of capacitors are used in many places. If you have invertors in RVs or solar panels on your place you will have lots of these capacitors. They generically are designed to be good and used for apx. 7-9 years. Other posters below have suggested instead of putting in a 370V unit, find one that is rated for 440V with the same mFD rating. That will indeed help prolong the capacitor life for a lot of the same reasons as shown in the video. Great information. BTW, ironically these things generally only cost about $10-20 and are often the biggest failure point in AC units. If you know what you are doing to put one in, it might do well to have a spare on hand if your unit is getting above 5 or so years old.
I'm not a HVAC tech, but I changed out my 7 year old cap that had been replaced with a Amrad and also installed a Amrad easy start as preventive maintenance in the central Texas heat on my 13 year old unit. I am replacing the contactor as well which is 13 years old just as preventive measure. That's on my list today.
I'm in South Texas....San Antonio to be exact and the darn near year-round heat is brutal. I'm also not a HVAC tech and I definitely know my limits and know when to call a professional. I'm also not a ASE certified mechanic, MECP certified, licensed electrician, plumber nor a computer tech but I do all my own work which is quite satisfying.
This is a good practice, that cap (7 years in service) was well past it's normal useful life, in my experience. Contactors do wear out as well, depending especially on their quality and proper selection for "wetting" capability, which accounts for contact wear.
I am going to subscribe. This video gives an excellent explanation of testing and why capacitors fail. I am a retired equipment technician and if we had a training officer like this in our company, it would have saved time and effort for our junior techs.
I'm of the opinion that capacitors only fail 30 seconds after you've left a job site. Even though you checked the unit and watched the AC run perfectly for multiple cycles after doing a filter change on a unit for the most pain in the ass customer you know. Because we all know "it was working before you looked at it".
As I tell my customers, "it's like your kitchen light bulb, it was working fine 10 minutes ago, but now it is burned out" They all get it at that point...
@@ramtek2702 It's funny you say that. Most mechanics are paid by the hour with no commissions or bonuses of any type at least where I'm from. There is absolutely no reason for mechanics to lie to a customer to just sell them parts because there's no insensitive for us to do so and we're usually so incredibly busy and have other calls to get to. The real problem is the lack of qualified mechanics these days has caused a lowering of standards when it comes to hire practices. In the last 10 years or so the industry has been floaded with hacks that just don't know what they're doing and they are "parts chargers" because it's the only way they know who to get something to work.
@@ramtek2702 Your first 2 sentences are correct, but the last sentence is wrong. The majority of homeowners don't know they are being deceived so they continue to trust the dishonest ones until an honest tech tells them how the other guy was cheating them.
@@briangc1972 Also, a good tech worth his/her salt may have to suss out the real truth with customers as they can also lie to a tech, hoping to get away with not having to say, pay much.
Not really. He mentioned he was heating it later on. Probably just holding a torch or other heating element below it. If you compare the before and after, you can see the label near the bottom has darkened significantly from the heating.
5:50 The energy stored by a capacitor is NOT held on the plates but, rather, in the dielectric in the form of an electrostatic field that causes polarization. This is electrostatic induction. A dielectric, by definition, is an insulator. If the rated working voltage is exceeded, the dielectric is literally pulled apart and the plates will arc as you no longer have a dielectric. When the plates arc, there is a vaporization/heating and that expansion is the physical damage on a electrolytic capacitor's can. Other types of capacitors physically fail in other ways. 7:33 The capacitance is not dropping due to a "foil breakdown". It's the dielectric that is failing which will then lead to plate damage. 7:57 Again, the dielectric is what is damaged by over voltage, not the plates. 8:03 The damage is NOT on the plates, initially, it's from the dielectric failure. In any event, please don't give electronic/electrical theory explanations if you don't understand it yourself.
Hey, the guy does not understand theory, he's a 'repair tech'. Just a warning, this situation is only going to get worse, MUCH worse. In ten years, nobody will know anything about anything. Good luck solving problems in the future. The complete dumbing down of the population has been successfully completed..
You are absolutely correct. However, as we both know, you will observe plate failure on every failed capacitor. That or a dead short. Which is likely where the idea came from. The good news is that HVAC techs and Electricians don't have to be electrical engineers. They don't have to know why the formula works, just that it does. The two things that bug me are the Cap not being rated for the peak voltage, and the fact that formula will change based on 50Hz or 60Hz. There's a decent chance the rating is RMS, but the formula is something that could get people who just go by this video in trouble!
Question for you though. You keep saying it's on the dielectric but isn't the dielectric in this case the (forgive my layman's terms) "big roll of foil" inside the capacitor. If you cut one of those open it's basically a giant roll with 2 thin sheets of foil and something separating them. What is actually considered the dielectric?
This is awesome. Concise, explains everything, no extraneous commentary or time waste. However, If you began by checking the capacitor and found that it was good, why did it fail? Secondly, when you evaluate a capacitor, how do you know that it will fail? which yours did and you apparently knew it, but what was the indication that it would fail?
See my posts below, he heated it (with a torch?). Please click 'like' on that post so it can stay at the top (when sorted by 'top comments') SO MANY also have this question. Credit goes to others' answers (replies) below that spotted it before me at 5:42, so I also posted this as a comment instead of a reply, so people can see it without searching and opening all the replies. Mr KL
Thanks for this, I recently paid a service technician $250 labor to replace my capacitor, it took him about 10 minutes, now I know where it is, what it looks like, how to tell if it's bad, how to turn off the current, and I looked on line and found out where I can buy a spare.
I installed my central A/C in my home myself 24 years ago. I am not a tech, just a DIY type of guy. 5 years ago the condensing unit stalled, I found it sitting there humming and unable to start. A little bit of online digging gave me the answer, and the capacitor had swelling on the top and bottom of the can just like what is shown in this video. I found a replacement cap on amazon for about 15 bucks and bought 2 to have a spare. Up and running in no time for chump change, and the unit is still running strong today, the only other thing I've done is put the gauges on it 2 years ago and top off the refrigerant charge. I talked to a guy who runs an HVAC repair service and told him how I fixed the bad cap for 15 bucks. He said he keeps a stock of those caps on his truck and marks them up to $49.95, and then there's the service call and labor. That's why you pay $250 for the same repair if you call him, and it is totally understandable when you consider his overhead and the fact that he is not in business to break even.
Most semi-densely populated areas have HVAC supply houses where you can buy a cap locally, so have the system back up and running, but if it's not expensive the prudent thing to do is just go ahead and buy one so you have a spare, especially if A/C not working would be a significant hardship on the residents.
After several years it's always a good idea to change out capacitors, contactors and relays, they did their thing, leaving them in is going to take out the larger more expensive components. It's also a good idea to go through a unit and get a baseline on everything for future comparison, no one does this, but most HVACR equipment comes from the factory with a start up check list in the installation manual.
I heard a lot of posible causes and personally the one thing I’ve been seeing over some years it’s that when you expose the capacitor to extended heat streaks periods,confined spaces(with poor ventilation)and/or very exposed areas to direct sunlight(no shade from sunrise to sunset),the “uf”rating diminishes dramatically compared to systems in well ventilated areas with some shade at least some time of the day! Maybe you should try out a test like the “Project Farm”guy and let us know how it goes…
@@aberobinson1 I’ve never seen a capacitor installed upside down,it’s there a specific brand that do that on their systems,or is it simply a “SPECIAL TECHNICAL CONFIGURATION” that some pseudo-technicians use? I have seen them horizontal but never upside down!
I’ll keep an eye out since I’m yet to see one. Today I took apart an old carrier condenser with huge capacitors (volume,not micro-farads) and they seem to be the original ones from when it was built,nobody ever laid hands on it since installed(and it was working well but customer decided it was time for replacement),seems that planned obsolescence it’s the name of the game now days,or as some call it “job security”…
@@aberobinson1 also pentair heat pumps Mounted upside down right above the contactor Dumb so they can fail and take out the contactor too Maybe even catch the oil on fire
Please share your thoughts on these four topics. 1. Adding surge protector to outside unit. We live in Tampa, the US lighting capitol. 2. Adding a "slow start" device to the unit. 3. Using Turbo 200 Motor Run Capacitor (made in USA). These have 5 year guarantee. 4. DIYer changing Capacitor. Thanks -- great video.
UEI is the best. I've only ever had 3 meters in my 20+ year career, all of them UEI and they all still work. I even dropped one off a roof once and it's still going. I see guys with the Fluke meters that cost double what I pay for my meter that does half of what my DL389+ does, I think that's the model number. Great meters.
Great video… very educational. I have spare capacitors for my furnace but never thought to get them for the compressor. I will be doing that this week. My furnace and ac unit are only 10 years old and the furnace has had one of the capacitors replaced twice. Thanks.
Hi I loved this video and especially your maths explanations. However there was one crucial piece of context that, while obvious to yourself and perhaps most of your viewers here, it initially left me confused. I"m like, this man's a magician, what spider senses is he utilising to know that a cap which he just demonstrated is good (and not just good but good under load!) is going to fail (and pretty soon!) =D The cause is that when you show your timelapse awaiting the capacitor to fail the vision is zoomed in and there's no visible sign of you presumably blowtorching the cap (also you didn't say how you were going to fail the cap).It wasn't until I rewound this once or twice that I realised there was browning of the label on the capacitor and that you must be applying heat. It's dead obvious to me now of course! but on first viewing that omission was confusing. It reminded me of one of my favourite lecturers who, on occassion, would confuse the heck out of us because he'd missed a small piece of important context. So many thanks for a video that I did subsequently follow, I'm only commenting to help and not criticism. Cheers!
@@DaddyBeanDaddyBean I appreciate your 5:40 and yet it also supports that context was missing because the failure timelapse starts much earlier around 2:38 (I started rewinding long before 5:40 trying to figure out the context). I guess I'm trying to say that this is about teaching being hard because as the teacher you're conveying information on a subject that you're already intimately familiar with and its hard to notice if a part of your teaching has unintentionally glossed over something that sets up the context for understanding. Its also ironic that his diligence in proving that not only did the capacitor get tested as proven working, but also proven working under load added further to my confusion of why it failed so quickly. I in the audience couldn't anticipate how this perfectly load tested cap was going to predictably fail (for example, perhaps he'd run it over-voltage in preparation for this demonstration). So please know I'm not crucifying him for a mistake, I'm reflecting on the challenges we have in teaching where we are fully aware of the context of what we're teaching and inadvertantly because of that familiarity not realise we've skipped over something that is foundational. I find it fascinating. Cheers!
On ACs when summer comes? or heat pumps? If heat pumps, I would guess not the cold itself, but higher start currents in the extreme cold? (or failed crankcase heaters?) Mr KL
Overheating seems like an easy fix for the design team. If only there was a nice big fan with high air flow just mm away from the capacitor that could be redirected to help cool the capacitors?
Some say that if you raise the capacitor can's voltage (like 370 VAC); will damage the compressor. Not so... The voltage on the can; is only the limit the capacitor can take. So IF you increase the capacitors voltage on the can; it will NOT hurt the cap nor the compressor at all. But if you lower that voltage; that's another thing. So many techs replace the 370 vac to 440 vac or even 600 vac, etc volts. And they say it lasts much longer. I believe that; as having been an Electronic Tech for TV's Radio's and even AC's; for 45 yrs. Retired in 1996. For what it's worth.
TL;DW 1. Capacitor is too hot; unit is in the sun or just is hot a lot. 2. Capacitors are expendable items. Hotter they run, the less they live. 3. Voltage spike, e.g. surge, lightning strike, etc. 4. Bad connection point overheats terminal and creates a failure.
The best way to keep your air conditioner running is to have this guy come out right BEFORE the cap fails - because he knows exactly when that's going to happen!
Great video! I’m sitting here in the Florida Summer heat waiting for a new AC. Going to be a Carrier heat pump. My Trane lasted 19 years with the usual TLC. Evaporator coil sprung a leak. It was a straight cool with gas heater.
Dielectric fluid main purpose is not specifically a cooling fluid. Its main purpose is to prevent conduction between plates of the capacitor. Lower powered capacitors use air as a dielectric. As with many fluids there is a cooling side effect With DC current the dielectric does not allow current to pass between plates and one plate will hold the charge for a very long time. This can also be very dangerous for those larger capacitors if they are assumed to be discharged you can get quite a big surprise if in stead they have a charge in the capacitor. I learned long ago like a gun do not assume the capacitor is discharged. Always discharge them by shorting the leads at least 3 times. When shorting the leads it will only discharge 1/3 of the charge at a time. Yes there will still be 1/3 of 1/3 of 1/3 of the charge left in the capacitor but at this point it is generally considered safe. When using AC current there is a charge then a discharge effect for every cycle there for creating the appearance of electrical transference. Its actually capacitive reactance. When coupled with an inductive motor it causes a phase shift to help push the motor through its magnetic phases. The explanation is more complex than I have time but do some googleing and you will find how that works I am sure.
I had always discharged them with a screwdriver. It was almost always uneventful, except one time I was in an older type of development, and when I discharged the cap it went off like a gun shot, echoing through the neighborhood for a few seconds afterward. I was sure the cops would show up, though they never did. I wouldn't have wanted that jolt to go through me, that's for sure.
Why aren't the units designed to cool the capacitor using airflow? Why aren't there heatsinks/fins on the capacitors? (especially with cooling airflow) In many devices, these cooling methods are applied to other electronics parts sensitive to heating so why design them such that the capacitors fail earlier than they have to?
It's connected physically to the rest of the unit so whatever heat is in it is going to get shared with the rest of the thing. And since they're $15 on amazon I'd guess a separate cooling system would be more trouble and expense than it's worth.
Because that would cost more and these days things are engineered to just last past the warranty, on average. Besides the idea is, a capacitor is inexpensive to replace, and not even soldered into the circuit. That is, until a pro tech makes his living doing it, lol. As far as other devices, very few non-commercial electronic devices use any kind of additional cooling measures for the capacitors, unless you just consider it a side effect of proximity if the caps happened to be in a fan cooled power supply where the fan's primary purpose was keeping other things cool like transistors and diodes.
It is called planned obsolescence. If the AC unit lasted 30 years, the manufactures wouldn't have future business. Watch the video on light bulbs. The companies agreed on life hours for the bulbs. Wake up to the intended failures built in to everything you buy, so you will need a new one. Cell phones are a prime example. Yes, there are technology limits to some things.
@chuck 8094 How about installing a muffin fan to blow air across the capacitor? Been retired 20 plus years but remember using slip-on fins on capacitors; do not know if the fins are still made but they help a great deal.
The solution?? The very simple is when motor start or stop, it generates a spike volt 370V x2 ~ 740V. So then it required as least 800V or 4 cap which is 2 in parallel and 2 in series. Moreover it also required a snubber for AC not DC diagram to protect and return these higher volt if the coil did. P/s: Also the vibra will make the statistics R then a dielectric grease and stronger contact from wire to cap.
Yes, increasing surface area of the cap can, or what it's thermally coupled with, will tend to increase lifespan, but it would cost the manufacturer money to do it and from an end user perspective, rigging that up might be more trouble than it's worth compared to just having another capacitor in stock and ready to install.
yes, especially electrolytic types, their life is rated according to max voltage, temperature and ripple current, any reduction of them increases life, in theory a plastic dielectric cap , especially small coupler or decoupler should last forever, if not used!, but if used within limits, plus a safety margin, still almost indefinite, these power start/run ones are a bit different due to various stresses on them
New subscriber and thanks for the education sir! I just had one fail on my 6 year old Carrier unit and it looked practically brand new, no rust or bulging. Put the multi meter on it and it was dead. Replace with a new American made capacitor and we are good to go!
I actually had one fail on me a couple days ago while I was standing there. No Cool call. Disconnect was bypassed. Once I found no power to outdoor unit and disconnect bypassed I went ahead and checked the capacitor and contactor/wiring. Then went over and flipped the breaker. Unit started up and ran normally. There was numerous trade businesses there on a remodel and the breaker was turned off not tripped. So I'm standing there watching system for a couple minutes and fan starts making a terrible noise. Go to check it when I noticed that capacitor popped. All in a matter of about 3 minutes. Tested close to perfect and then popped after 3 minutes of run time. Replaced it, ran it through some checks, didn't find anything else wrong with the system that would cause the issue. Condenser in the shade on an 85* day.....
Yep, lucky it failed while you were still there. I'm inclined to say caps are consumable items that should be replaced periodically before they fail, based on age. After a few years is reasonable, IMO, despite they test good and work fine.
Great explanation. I have replaced my AC capacitor twice now in the almost eight years I have owned my home. In both cases the capacitor was visibly expanded at the end.
Replaced my old systems 11 years ago. They had been installed in 1965 and kept their original capacitors. They were in a well-shaded area with free air movement.
@@joecooksey4331 Great point. When I read about PCBs, I soon understood why they banned them. Same with R-12. Without the ozone layer, we would soon all starve. Earth would look like Mars, only with water.
I keep finding the Geico lizard's mummified body across the cap's terminals here in Louisiana... The lizard jerky is hygroscopic and absorbs water in very humid conditions and begins conducting again. Over & over.
Most educational A/C repairman I have ever seen. I'm an electrical engineer and I say he knows his stuff.
Thanks so much Henry and make sure to check out our articles and quizzes at www.acservicetech.com thanks!
I too know that formula. That’s something one would share if getting payed as a teacher.
A little tip from a former residential tech, replace all 370 vac capacitors with 440 vac capacitors using the correct microfarad rating. IE: 35/5 mfd. 370vac dual capacitor fails, replace it with a 35/5 mfd 440vac capacitor. I can't ever remember having a callback on the same unit for a repeat failure in 9 years of service. Good luck guys!
if you put a 370 on a 440 , you will kill the compressor
@@rodeoclownobama5796 but why?
Not even 440, but at least 370 * 1.41 = 520 V. Use 600 V capacitors and you will have no problems.
@@rodeoclownobama5796 huh? the point is to upgrade the voltage from capacitor, not downgrade
@@rodeoclownobama5796 lol, you sound like the uhaul tech who told me I was going to "over juice" ...his exact words.... and burn out my trailer lights by using a larger diameter wire...as if somehow magically the trailer lights will use a dangerously high amount of electricity just because the conductor is larger.
I'm a former instructor, still running service...This is an excellent video...Better than most, clear, easy to understand, and well done....Thanks again for what you're doing.
Can you tell me this, please. Is the capacitor an all-or-nothing type device, meaning, if it’s good, it’s good, and if it’s not, it’s dead OR can it become inefficient over time and operate poorly, degrading the efficiency of the A/C and driving up costs?
@@Unknown17 Yes...They can weaken...The Micro Farad rating drops off more so than the voltage...When it happens motors run hot, if at all...They have meters that can check them...10% under...It's bad for the motor...I replace them if not right on the plate rating...Once weak, it will only get weaker.
@@vernroach3413 Thank you! Just had one die on my home unit the other day, which was replaced. Even tho’ I’m a pretty old guy now, there are some holes in my education and life experience, and this is one of them. Oh, I also suck at knowing my flowers and trees. I don’t know an Ash from a hole in the ground, ha-ha. ‘Predicate ya!
@@Unknown17 You're welcome friend...I'm aging out myself, late 70's, now doing favors more than actual service anymore...Helping people save money, keep them from being gouged and the gougers are out there...Still learning, still complaining, and still wondering, what the hell is going on...Be safe.
Will a bad contactor shuts off the compressor fan but the compressor will still run?
I am amazed how much knowledge is available on the internet for free from folks willing to share it. Thanks for making these videos. Also, thanks for providing the Amazon links. Looking through them reminded me that I need to get some vacuum pump oil and pick up a swaging tool for an upcoming job.
I agree. I managed to install my minisplit completely on my own. Aside from wiring the outdoor unit up to the mains power, as that was done when my entire tiny home was wired.
I hate to break it to you, but all this information is located at the Library as well....for free. ;)
@@JediOfTheRepublic Actually, that is not my experience. In 1989 I went to several libraries looking for books on sizing and installing central AC in a residential home. I had bought my first house and wanted to install central AC. I went to the largest regional library in northern Ohio, to the branch noted for science and technology materials. I went to the Cleveland Public library main branch (two large buildings, 8 floors). At the time it was reputed to be the largest library in Ohio.
Neither library had the type of book I needed. They did have a book suitable for engineering students that required calculus, but not the practical info one would need to install central AC. When I asked the librarian why they did not have such a book, she said that it was probably too complicated for most people. Now, we have high school drop outs in the HVAC trade, so I know it isn't rocket science.
I ended up finding a text book on the internet (this was pre-YT, and in the days of dial up) that was intended for trade school students. It covered car AC, residential, commercial, etc. from beginning to end, hardcover and about 3" thick.
@@menchelke And, with a little care, turning off the main breaker or pulling the meter, you could have done the wiring as well.
@@BryanTorok If you look at my channel, I got crud quality vidoes too, you can see my install, but I'm disabled, and it would look like crud. The guy I hired, does clean professional work. I have the industrial look with exposed conduit everywhere. I'll make repairs, do outlets, ceiling fans, etc. But not a full install with conduit bending, etc. Guy did it over 2 days in 110 heat, as no ac, as there was no electrical. Would take me like 5 years at my pace and still look like crud.
I honestly can't even remotely consider why anyone would thumbs down this video... It is distinctly, one of the absolute best explanations on YT for value, reason and explaining the math behind it. Job well done Sir.
simple to explain why the thumbs down - it is u -tubes fault. if you give a thumbs up you will get blasted with stuff similar to . since i just was interested and not wanting more similar, thumbs down - NOT because its a bad video. stupid the way utube does things.
Probably down voted by an AC guy that don't want people to know how easy and inexpensive it is to replace! He loses business over these types of videos. Emergency call, service, and part $450.00 for something that can be fixed in 10 minutes and the cap is under $20.00.
@@williamkechkaylo7915 Safety glasses on head vote.
No.
@@rustynail6819 or jealousy
When I was a kid the capacitors lasted the entire life of the unit. I've seen caps so old the only reason they had to be replaced was because the 25 year old terminals had rusted through and you couldn't get a connection on them anymore. Those caps were oil filled and weighed a couple pounds. They were also a lot bigger in physical dimensions, a 30mfd was about 7 inches long oval can.. The caps we have now sometimes fail in a year and feel like they're filled with air.
One word....CHINA.
I believe that they used PCBs and thats why they last much longer.
@@vernroach3413 It aint where it's made, it's how it's made. My Sony receivers lasted 30 years it still works
@@agsession7664 Depends on what is made too...I do believe Sony is from Taiwan...Far better than China...South Korea for the most part, good products...Mexico, depends on what it is...Most receivers will last for years, no matter who made them...It's just a receiver...They're not under the stress some products are.
@@curtishuzarewich7033 I think it was actually because they were foil caps, not vacuum deposited metal films on plastic film. Could handle current overloads without overheating. IMO.
Mr KL
Thanks. I had a string of cap failures on a new Trane sysyem. After the first 3 or 4, the AC guy measured voltage. I had a bad street transformer and 1 leg was 115, the other leg was 132. Town came and replaced it, no problems ever since.
Been there done that. Power companies don't mind coming out of you don't mind waiting
I always keep a spare capacitor at home. After the first $250 bill for replacement, I learned to do it myself.. Only a $20 part so cheap to keep a spare. In Texas they are the most common failed part on a home AC and they charge an arm and a leg to come and replace it. Literally takes 5 mins to replace..Easy to test with a volt meter..
Maybe it would be a good idea to figure out why your capacitor is failing so much
@@jakev1972 It's in Texas. It's hot here, like a lot. High ambient heat shortens electronics life.
Yeah, Texas is hot. And they aren’t failing a lot. I’ve only replaced 2 in 10 years. But there so cheap, why not have one on hand instead of paying a high prices service charge and having to be without AC overnight or more than 8 hours in 110 degree weather while you wait for that service call…
I have spare capacitors and replace it as a planned-maintenance item (PMS in the Navy as an ET is planned maintenance system, fix it to keep it working when you never know when SHTF).
Reduce the temperature of the cap by shade, or maybe heats sink or reposition
For anybody wondering where the numbers come from, recall that impedance of a cap is 1/(2*pi*f*C). Plug that impedance into Ohm's law and rearrange to get C by itself, and assume 60 Hz. Dynamic testing like this will be much more accurate in a real world situation. Brilliant video!
@ spelunkerd
anyone NOT anybody
One is the Cardinal Number
One is alive
One is unique
There has NEVER been one like you in existence before you were born
There will never be one like you after you die
You only have 'one' soul - thus you are 'one'
Every body is the same : Rotten and stinking after four days
'Body' refers to a DEAD ENTITY.
You will find every'body' in the cemetery.
Unfortunate your education system is pathetic and 3rd world standard -
designed to manufacture ignorance and dumb down the population
The reason why Latin is not taught in school these days is so that people
do not understand the origin or the real meaning of the words they use.
Had you been a student in my English and History classes you would
have a better grip and knowledge of the English language - and North
Americans are among the least educated of all the OECD countries-
scoring at the bottom end - where 1 is the highest - 50 is the lowest.
The US is not even in the top 30 of the best educated.
Thanks so much. You are the only one who answered the question on every one’s mind ( except for the Newtons)
I'm missing something, as solving for C= I*2*pi*f/V. The 2*pi*f is 377, which is 1/7 of the 2650 number. What fudge factor is missing?
@@f.hababorbitz Remember it's in the denominator, so you need to invert the number, 1/377= 0.002652. Then note that for simplicity he changed units to get rid of micro units by multiplying by 1,000,000.
@@spelunkerd Thanks, to much manipulation in my head and not seeing that I had 1/C, and did not invert the 2pi*60.
Such a great lesson for every tech who now can't sell them a new fan motor because the homeowner just watched this. Very good video.
I’m a Contractor now but been in the HVAC trade for 18 years and I still learn from your videos, good stuff and some of it I’ve forgotten about. Thanks for putting in the effort!
On high end heat pumps a soft starter is used instead of Start and Run capacitors. But if manufacturers of lower end units fix the problem of capacitors always failing then a ton of service technicians would have very little to do.
Craig, you have a natural talent for explanation and always demonstrate these concepts. I'm a visual learner and appreciate it. The Mini Split book is one of a kind!
We didn't get much time to chat, but I hope to see you next year at the HVAC Symposium in Clearmont!
Looking forward to it!!
Thank you for the great content! Having a clamp ammeter plus a good DVM makes checking the capacitance very easy as opposed to cutting the power, discharging the caps, disconnecting the caps and using a meter that can measure capacitance. I also like the fact that your way tests the cap under load. With the supply chain woes I think I'll buy an extra just in case. Everything in your A/C system is designed to fail after closing time on Friday in August.
I love your closing comment. Isn't it the truth. I'm not an HVAC guy but I maintain a surplus of new and salvaged items around the house in those emergency situations.
Truth
Also when record temperatures (120F)
HVAC school was insisting caps fail due to overvoltage (transient / surge). When I suggested it was heat, I was essentially told I was stupid. I've had really good luck replacing with two capacitors to spread the heat load. I also agree with the commenter who suggests caps with higher voltage ratings. Everything I've seen suggests heat is the real culprit.
An apt. complex installed all condensers on roof, shingles. The heat destroys them in 2 years, a rotating problem. They decided to put all 114 of them back on ground. No more fails.
Your instructor has one of two things.
1.Stick to the timeline for the next class
2. Arrogance to the challenge
3. Both
@@danielabilez3619 It is heat. I am EE trained and HVAC tech. Try placing Condensers on roof with lineset and watch the failure rate skyrocket. Recommend the 440 VAC rated.
Yezzir, Heat as a result of... but heat gets all capacitors
yep, but excessive current through(strictly in and out, a cap shouldnt pass current through it directly) and/or overvoltage can cause internal heating as well, eventually destroying it , some motor caps are rated for intermittent start use only not 'run' .. you have to use the correct type
Thank you, your video is by far the best at explaining why capacitors fail. When I built my house I purposely placed the AC unit on the north side of my house away from the sun. Not only does it help save capacitors it also lets the unit run more efficiently.
I see several comments that share my thoughts here: A. Excellent delivery of information. No unnecessary pauses nor tangents, you stay on point and you are very concise. You ought to teach HVAC/Electrical if you don't already. I am very impressed. Oh, and you answered my questions. I had no idea what dielectric fluid was before today and that explains the size and shape of transformers on telephone/electric poles. Pure physics inside a capacitor...surface area for storing electrons. Color me schooled. Though I'm now more curious than ever.
Excellent video. I replaced my 20 year old 30/3 MFD capacitor after condenser fan would not start (but would with a push). Cleaned all connections and replaced capacitor. Old one measured 29.8/4.7, indicating a leaky capacitor on fan side. New one measured well within 1% of spec. I also measured total amps to condenser unit before vs. after repair which dropped from 8.9 to 8.15. System runs great now.
Hands down this is the best video I have found on youtube for this topic. The guy didn't go to deep but just deep enough to give enough of the math behind what was going on to arm a DIY'er with with what they need to understand when replacing these caps themselves (or at least dealing with an AC contractor.)
Wow. Excellent presentation on capacitors. I have two 3 ton AC systems at my house. Last week one capacitor failed. AC service tech fixed it and 3 hours later after he left the second one failed on other unit. I remember looking at it and it looked bulged on the top and "wet". But tech didn't realize as far as I can tell now what the telltale signs were that it was bad our about to go bad. My take away from this experience is that after a $308 service call I need to buy spare capacitors. Which I have now done at a whopping $16.80 each. These should be treated light light bulbs and every homeowner should have a spare on hand. If AC won't start it's super simple to swap out cap. There is an 80% chance that is the problem and you are back up and running right away without having to call for expensive service.
If you don’t mind me asking, where do you buy these spare capacitors? After watching this video I had the same thought of having a spare as a lot of times that is why a system goes down.....thanks
@@trailerparkcryptoking5213 amazon, ebay.
Are there any safety concerns when handling a capacitor?
@@sktoh4469 yes. if the capacitor is charged you do not want to short your self across it. The standard technique for handling capacitors especially "power capacitors" is to ensure that you short the terminals to dissipate any charge. Easily done by placing a good conductor across it like a screwdriver shaft.
@@bartoncourcier414
No don't do that. Better for the cap if you use a resistor across the terminals.
The screw driver is a last resort.
Finally! In my 48 years of HVAC I witness someone who knows what he is talking about. Heat and life, I have argued, are the only two culprits of failed capacitors. Cheap manufacturing is a culprit, but only because the cheap caps can't take the heat. I use only USA made caps in 440v. I have had repeated failures on a few condensers, and after moving the cap to the inside of the condensing coil where the fans air movement can cool the cap off, the failures quit. By doing what RUUD/Weatherking has done by making a hole in the cabinet and slipping the cap into the airflow. *You'll need to make sure the leads aren't exposed to the weather.
Job well done.!!!
Oh! Just one more thing, though it is tedious- "2652" is more accurate for me. A long time discussion I'm sure you have had.
Heat reduces the life of any component. If the manufacturer wanted to do something about that, they easily could. There's a giant fan in the condenser... How about putting a couple of vents in the electronic compartment so there's a bit of airflow from the fan?
Manufacturers tend to source from the cheapest OEM parts to line their CEO pockets. You get what you pay for,
What I saw regarding the voltage measurements reminded me of something I first read as a military guideline for component reliability. I was surprised, but the saw other supporting information, including and especially the Arrhenius studies of temperature effects. Anyway, what I then decided to make my permanent memory, is that you never use the components at the listed ratings! You design your systems to stress the components only to 70% voltage and 70% current relative to the manufacturer listings. In other words, consider the listed values as maximum, not as safe continuous ones. In the shown case, the 365 V appearing on the capacitor would require 550 V or 600 V rated capacitors. That assuming the manufacturer would not cheat and label their capacitor higher voltage, knowing that the users will do the derating...
Great tips and outlook!
Do you mean his actual was 365, so then use a 5-600 capacitor?
@@bryanhauschild4376
Yes - that is what I saw on on the meter display in the video. If that sounds wrong, just think what happens when you have an inductive coil (motor) and the capacitor in series. Depending on the two values, there is a resonance at some frequency, maybe a harmonic of the line frequency. In resonance or even near a resonance, you get an increase in voltage over EACH component. In theory (infinite Q, zero resistance), the voltage would climb to infinity. In practical situation, the circuit Q is not infinite, but some over voltage is developed anyway.
@@InssiAjaton could you explain resonance further? Is the resonance you speak of creating sound too?
@@bryanhauschild4376 Hey Bryan. Resonance is where the inductive reactance, XL and capacitive reactance, XC are equal to each other. At this point, the voltage across the inductor and capacitor are equal, but the voltages are 180 degrees out of phase. This will create minimum impedance in the circuit where the current is the highest which is only limited by the resistance of the winding. This pertains to a series circuit where the inductor start winding and run capacitor are in series. It has nothing to do with sound.
here in the US southeast im seeing alot of capacitors fail within the warranty of the unit, ive noticed that these capacitors are made by the same company, we replace them with a cap made by a different company from a different place and they last significantly longer for some reason
EXCELLENT video! As mentioned by @classic Pontiac37, sometimes using a higher voltage rated cap will make things last longer. In petrochem control systems, I've seen blown out power supply filter capacitors that the manufacturer pinched pennies on and were within a volt or 2 of the running voltage. Running "rated voltage" that close is not good in HVAC or in production plants running 24/7. We solved that problem by replacing all of those "too tight" VDC filter capacitors with ones almost triple the running voltage. No more failures.
Thanks for the video! My HVAC capacitor recently failed and due to the recent heat wave and we could not get a vendor out. Was able to get a capacitor and install it with the help of videos like yours (locked out the circuit, waited, then tested for residual voltage). the old capacitor had good shape but the top was wet from electrolyte leaking. Thanks!
He heated the capacitor at the bottom.
It wasn't made very clear in the narration.
I saw many comments asking this, and after seeing several comments that he did actually mentioned this, I replayed the video until I found it mentioned vaguely at 5:42. I assume he heated it with a torch...
Good demonstration! Fun to see the disconnect feature in action. Thank you!
It would be very interesting to repeat this with a thermocouple reading the case temperature at the moment of failure...
It likely exceeded the lifetime max temp rating, but that is how accelerated life tests are usually done anyway.
I don't know if you are inclined to try this again. Maybe extend the leads and place it in an enclosure that you can heat evenly and gradually, until it fails?
At the minimum, we would learn how much 'headroom' we have above 160ºF, and when 'lifetime' becomes '0' hours...
Mr KL
Yeah that wasn't clear at all. "Due to high heat" . Not "Because I am heating it"
Thanks for the clarification.
Our made in China capacitor failed in our Goodman unit at 6 years. The salesman at WW Grainger said 5 years is usually max life. New Dayton replacement is also made in China for $ 38. I bought 2. 1 for a back up for the future. Thank you for the great video, and informative comments from electronic geniuses.
My God, man. Don't keep sending money to China for junk capacitors. Buy AmRad US made capacitors.
The first failed one was rated 370v right? You DID replace it with 440v hopefully.
All electrolytic capacitors have a limited lifespan, don't let any snake oil salesman tell you otherwise. It doesn't matter where it's made, it will fail eventually, physics doesn't care about nationality, buy quality caps from manufacturers with a track record.
@@Nomorage So if the american made capacitor prematurely fails should I stop buying american capacitors?
@@Nomorage China can and does make any component classification ranging the entire quality spectrum. They are the #1 country for receipt of the rest of the world's outsourcing needs. If you want premiere quality just spec it so, they will make. Multi thousand dollar Trek bikes may be assembled in Wisconsin still, but the frames come from giant state of the art Chinese factories now, made to Trek specifications.
It's good to know that there are still techs out there that care like I do about the trade...Almost 30 years myself.
For a callout work, we discovered the facility had a 60 Hz ceiling concealed equipment in a 50 Hz mains power source country and over 80% of the units had swollen & bad capacitors. Apparently, they have been having the issues for a couple of years since commissioning. Once they are changed, the units work just fine. Recommended all capacitors to be changed with the scheduled routine maintenance to prevent downtime.
Excellent video. I have told customers for years the biggest killer of capacitors is heat (I'm in Florida) and the fact that many service techs don't check them to see if they are getting weak. When i was younger it seemed more common for people to have their systems checked/serviced/maintained in the spring as a preventative measure, now they wait until the system breaks down.
Don't you think it is silly or a crime for a person to have a repair person come by to check their system every spring? Old ladies and old men having some unknown dude come into their home to rob them when they come in to use the bathroom? Let alone come up with a bogus replacement and never offering to even show them the defective part. Why don't they build them right in the first place. Solar panels last 25 years and you don't need a yearly service call. The days of constant repairs and checks are over hopefully.
@@timsteinkamp2245 Seems a bit unfair to compare solid state devices to HVAC.
@@AvgDan My comment was about the idea of having a service technician come into your home and verifying the unit will work for the next season. I'm not talking solid state or HVAC but just the idea that you have to allow a person into your house every season to check us out. Even so there is no real guaranties. You can do a preseason check and it can still fail.
Thank you. My AC broke down in 113F (and climbing) weather and my multi-meter doesn't read capacitance.
The formula you mentioned saved me from buying another multi-meter. The way you explained the causes of failure is amazing.
I have seen a catastrophic failure of a cap from a lightning strike. It was the start cap for a deep well motor. It literally blew the top of the cap off ,which caused it to blow off the top of the control box. All that was left was the metal can and a spiral of the electrodes and dielectric material hanging out of the box. As a rule of thumb for me I always replace the starting caps on equipment over ten years old.
That happens inside hvac units as well. They sometimes blow up completely leaving a burnt oily mess everywhere
@@GonzoDonzo Seems like incredibly poor design, especially when it can be prevented. Is there a particular reason that contractors put with this failure mode for so long? An incentive, of some sort? Perhaps?
@@exgenica the old capacitors filled with nasty oils that were many times larger, rarely failed. Contractors dont have a choice. U can buy better quality but they still fail. They are like the old incandescent light bulbs. It should last for years but sometimes they burn out a week after u screwed it in.
Generally its indicative of something else going on as well but its the weak link in the chain and will go first
Sounds like all of the links in the chain are getting weaker.
@@GonzoDonzo said, "Contractors dont have a choice."
Contractors have the power of unions, professional organizations, conventions, and even individual feedback to motivate the manufacturers to reduce these field problems in future A/C designs.
Those that haven't provided that feedback to any organizations they belong to and to the manufacturers...have some responsibility in the problem still being as big as it is.
The best replace ac capacitor video. I had money go put 3 years ago and didn't know anything about. A friend on a phone fall told me likely the capacitor. While the a/c man was fixing I told him ot was the capacitor and he confirmed. Charged me 430.00 to replace A $15 part that I could have replaced just as easy. Expensive lesson learned.
Yup education is not free.
It is interesting that in 2022 nobody has invented a capacitor or replacement device/component that lasts 5x longer or even not burn out. Nice video - impressive.
Whenever I replace a dead cap on a relatively new unit I always get one with a higher voltage rating if possible (30-40%). Inductive kick always exceeds the rating but because it's very brief it takes time to damage the dielectric material.
2022? This should have been done decades ago. Connector design, enhanced cooling, properly spec'd voltage, unit failure chemicals containment...the whole bit should have been properly designed a LONG time ago. Putting up with all those separate failure modes for decade after decade seems very hard to justify.
They have, but other types of capacitors, particularly for high voltage, cost a lot more.
@@wiregold8930 At my place of work (rewind shop) we've noticed that the 400 VAC run caps (on 240 V. motors) don't last anywhere near as long as same rated 450 VAC run caps. Also, If any cap measures lower than rated capacitance, you can guarantee it's on the way out.
Excellent...Thank u.... Here is a thought.....why not make a capacitor that does not fail.....seems possible.
In high heat (70C) or high voltage breakdown, it is the polypropylene that melts. When it partly melts it creates a weak spot that has a lower withstand voltage, letting it get even hotter.
6:36 "If this shield is in the sun all the timer" or if an A/C repairman is holding a torch to the bottom of the cap, it's gonna blow! I gotta say, the wealth of information you shared just then was outstanding, not something you see everyday. Thanks!
That explains the burned label.
Took my first cap apart in the late 70's - was amazed. A friend called me one time in the early 80's ... got an estimate of $650 to replace a compressor. Cost $5.49 for a cap. Moved into my house in 88. Replaced the cap every 5 years for quite a while. Went from the oval shaped unit to a round one (Oval - out of stock) Round one still running after 10 years on my 40-year-old unit. Maybe I need to move the cap to the evap line. Very good presentation -Thanks
do you remember that PCB smell when they burnt? nasty!
@@randyosborn284 Was that PCB? I used to smell a small from Fluorescent Lighting ballasts in the 70's 80's and early 90's that I assumed were PCB's, but wasn't sure, the caps In my AC unit were pretty tame. I got a feeling it is some other hideous noxious oil now. Maybe not. It did have some kind of vinal smell though
EXCELLENT video. To the point minus fluff - WELL DONE. In my working days, I spent 17 years as a A/C tech. I also am a electronics tech and have been for decades. I did NOT know that formula. NEVER heard of it. I see it is ohms law with the 2650 number added in. Curious as to where YOU learned of it. You can bet I will NOT forget it. Also, 100% agree that replacement capacitors should be rated 400+ volts - ALWAYS. This is especially true in the desert southwest where I am. Here, I also used ONLY desert rated ball bearing fan motors. It MATTERS.
This 2650 stumped me for awhile too and it is really 2654 not 2650, but close enough. Here is where it comes from. V=I x Xc (capacitive reactance) and Xc=1/(2*pi*f*C) where f is 60 cycles per second. 1/(2*pi*60)= 0.002654 so Xc= 0.002654/C. Therefore C= I*0.002654/V which is a value with many leading zeros (microfarads). To get rid of all of those leading zeros just assume the answer is in microfarads by multiplying the 0.002654 by 10^6 (1,000,000). Hope this makes sense.
I've seen capacitors fail when the "operational smoke" is released. I've also seen this happen to resistors and other electronic components. If a way can be found to make the smoke containment more robust, I believe component life could be maintained indefinitely.
The Magic Smoke is indeed a fickle material in any component it's used in. IBM had replacement smoke they sold, give it a google search. The hard part was getting it back into the part :| Big bucks job there.
I noticed our clocks flashing on appliances. The was a power outage of some kind.
After youtubing a bit I ended up using the multimeter and found the capacitor blown. switching out our capacitor worked. We were up and running on a friday evening. I just made it to the supply house that had one with minutes to spare.
I watched your video for a better understanding. Thank you for sharing your knowledge with the diy’ers of the world
LOL - I ALWAYS wind up at the last minute by the time I finally learn what I need! The clock is ALWAYS at 15min til closing, no matter HOW much earlier I started the troubleshooting!
Mr KL
Good for you. Now order a spare cap and keep it as a spare. Cheep insurance.
Re: corrosion. With automotive headlights it used to be pretty much routine to apply an anti-moisture/corrosion material to the connectors. Seems like for decades the A/C industry has (intentionally?) used the wrong design connectors and not properly advised sealing the connections to reduce corrosion.
Plus needing one hand 2 inches wide and the other with 7 fingers to change the headlight bulb from my experience and without touching it also with halogen.
Well it's a good thing that HVAC units aren't driving on roads sprayed with brine in the winter and exposed to all the extreme vibration and other contaminates that motor vehicles are on a daily basis.
Obviously the outside condensing unit is stationary, sealed better and therefore shielded from all the nasty things automobile electrical systems are exposed to.
Hence the lack of protection seen in mobile applications... yet not always there either due to poor quality manufacturing, cutting corners, and of course the TH-cam graduates who don't have all the facts, tools and materials.
But by all means, please do yourself a mental favor by applying heat shrink insulation and dielectric grease to all of your HVAC electrical connections and put a sun shade over it.
It is just a heat pump after all.
@@rjbradlow Trailer Reefer units do. ;-)
I suspect they do use different connectors though.
@@michaeld5888 I've never had much difficulty with headlight bulbs or bulb assemblies. Guess I've been lucky. Thanks for letting me know it can be a problem.
However, for "and without touching it also with halogen." When handling halogen bulbs, I use gloves if I absolutely have to touch the glass envelope. If I can't, I try to clean oil contaminants off the bulb as much as possible before I seal it up. Many people don't know that even fingerprints from skin oils can significantly reduce the life of halogen bulbs so that's another good bit of info you've brought forward to people.
@@rjbradlow So...just because there are additional issues in a different environment, you get all sarcastic and mean and *don't even try* to solve even one of the problems? Sounds like a Millenial talking.
Great explanation. I serviced commercial refrigeration and AC for years. I don't have nearly as much experience with capacitors. I gained a lot of understanding from this.
Careful of those Chinese capacitors. I bought one for a motor I was using for a project and it was much lighter then the old one. I used it and it lasted a couple of starts. For giggles I cracked it open and it was a 240volt 5uF X/Y safety cap typically used in ceiling fans crudely soldered to the lugs.
Why did you trust it in the first place? What did it cost, like 89 cents?? Don't use cheap shit! Easiest lesson ever!
@@paulcopeland9035 The cap I wanted was on back order and I thought the cheap one could hold on until I got the proper one. Wasn't for a A/C or anything like that. It was for a wood turning lathe I built from scrap.
True. Replaced mine a few times, sometimes Geckos were the culprit. The last time I put a universal motor in and had to wire 2 capacitors for it. Worked ok but it failed. Finally called AC guy and he replaced it with a US made larger capacitor. Was a bit expensive but he did say many of these capacitors out there are China ones and this one was warrantied. Had some loud starts and stops for a bit, not sure why but it stopped and no problems.
the new chinese caps are junk, trust me, been doing hvac for 20 years, seen them last a week
I just changed that very same 45/5 capacitor on our AC unit. It was open on both sides. And I verified it was open, out of the circuit, using a Fluke capacitor meter. $26 dollars later we are comfy again... Thumbs Up!
I have to interject as I have seen high current burn out hundreds of capacitors over 20 years. More accurately the cause was power loss and internal heating due to high ripple current. The ripple current degrades the capacitor by raising its internal temperature!
Power loss and high ripple currents doesn't sound like a scenario that applies to HVAC.
As and Electrical Engineer, you did a excellent job of explaining the use and failure of a capacitor.
Great lesson. I became more knowledgeable on capacitors after watching this video.
Nice video.
Old AC tech told me tune ups are a racket....He said corrosion causes leads to have higher resistance and causes the most problems. Just turn off the power..remove every wire / connector you can get to and clean the contact area. Also clean out debris and clean coils. Been doing that every spring and my 27 year old unit is still going strong.
My capacitor failed and was told it was going to cost $220 to repair, but it would be a week to repair. I looked up the capacitor on Amazon, cost $18 and a day later I installed it in 5 minutes. Been working ever since. I did order another, just in case.
My experience is that Chinese made capacitors have very short lives. I've had problems with the capacitors on my pool pump motor. I just bought a made in the USA capacitor, we'll see how long it lasts?
@@larryross1819 iPhone is made in China. It's not what's made there it's quality. Rely on reputed known makes.
Erik, I just had an A/C tech tell me $330 to replace a capacitor, I showed him I could buy the SAME item from Amazon for $21. He told me his boss forbids him from installing such. Blamed Bidenflation and the need to be profitable.
You could buy 2x 10µF/400V and in parallel of 5µF/800V, also 2x 90µF/400V and in parallel of 45µF/800V and hold all of them in the ground to prevent vibra. That is it.
@@chipdenman863 needing to be profitable IS a huge factor. I could clean my own house for about $1 worth of cleaner or hire a person to do the same job for $60-$100. It's always cheaper to diy. Don't hold this against them. They are highly trained pros that must charge for their time wether or not it makes sense to you.
I have lennox unit from 1979 still running at my house. I've changed every part on the unit except for the compressor and the original 45 MFD run capacitor (separate capacitor for the fan motor and compressor). That 45 MFD capacitor from 1979 is HUGE and still running like a champ! I check it every season. I am of the opinion that ever since capacitors were made smaller and smaller they fail faster than ever. Less surface area to dissipate heat. I know it's more convenient to make them smaller, but I feel it has reduced their lifespan.
In 17 years i only ever replaced 2 of the old style capacitors that were much larger. I know they had some nasty stuff inside them but they were rock solid
Yeah ive seen 30+ year old caps right on the momey, new caps commonly fail in a year or two
I LOVE your detailed explanation of the capacitors and how they work. It helps me understand and feel more comfortable in diagnosing these problems.
I was a power supply design engineer in 1984 when capacitors were blowing up. It is all simple once you know the answer. Our caps had a wire welded to the foil making dissimilar metals. The end seals were epoxy with too much filler. The PCB cleaner was getting past the seal to attack the weld. During high ripple current the caps would fail. I don't know if this is why Sangamo capacitors in GA went out of biz.
In the 80's my a/c blew a capacitor each year. The fault was power spikes and brown outs (oe so I later learned). Replaced a perfectly good Frederich with an incredibly awful Lenox. If I knew then what I knew now.
Wow poor design and I'd say that's why they went out. AC mylar caps or other like electrolytic?
@@flaplaya electrolytic mil spec
China is why that company shut down I am betting. Buying 1,000 capacitors for $2 is a massive selling point. And a price US citizens simply will not work for. Without competition, that company would have corrected flaws in their designs and would probably still be in operation today.
By the way, exploding capacitors still has not been solved. lol
I am no designer, but I am a repair tech. Mosfet failure alone can cause a "runaway" current which can have you cleaning a board of capacitor remnants. Its not very common, but they can still detonate.
Most of them simply swell or purge their dielectric. Most exploded caps I come across are found oddly in audio amplifiers' output stage.
The caps tend to be placed far too close to the amplifying mosfets. And when people run them under 4 ohm loads or lower, the caps heat up dramatically.
I remember D mos from siliconex blowing up in my designs in 1984. But then International Rectifier FETs came out and were bullet proof.
Finally a no b.s. video of how things work and why they don’t…Thanks ! You teach like I do !
Thank you very much for your encouragement!!
My old PC monitor went black...Because of this video I figured why not look, and found 2 bulging capacitors, soldered in new ones and now have a spare monitor. Thanks!!
Now I understand WHY my 3-yr old unit failed suddenly. Thank goodness I have an annual service contract. Great video!
I'm an HVAC contractor and I would like to give a warning to some of your viewers about "made is China capacitors" sold online. Being in Az with our excessive heat, I have customers that buy and keep spare capacitors. Unfortunately, when buying online, you frequently don't know what quality you are getting. I have seen customers install low quality capacitors which then fail shortly after and sometimes burn out the windings in the compressor. If you buy capacitors online, be sure you are getting the made in USA brands. They cost 4 or 5 times more, but they do last longer and they are a lot cheaper than a new compressor.....
Don't bring your Chinese hatred in this topic because if you purchase the capacitor from a reputed chinese company it will work just as well as American made but will definitely be cheaper than American one.
yup. china caps will burnout in less than 1 year.
@@sunny6630 I have no hatred for anyone or any country. I am a licensed HVAC contractor and I stated my real life experience. For you to accuse me of hatred, you are showing your own ignorance of the facts and unwillingness to face the truth. I mentioned that the American brands do cost significantly more, but they are worth it because of the consequences of using poorly made, cheap parts from China.
Agree
To be honest the world over knows Japanese Capacitors are best.
This video really saved me. Yesterday, my run capacitor failed, and I immediately knew why it failed and how to replace it.
As an engineer for 50 years, I've opened a lot of blown capacitors. Dielectric failures primarily, then melted foil due to high current surges, esp vintage caps. However in one case, I had a 900 foot deep well pump replaced at a very high cost for me. Later I discovered the removed capacitor in the control box was the culprit. The rivet holding the terminal was loose. The cap was intermittent. The old pump was fine. Aghhh. However its not good for the motor to eat current without starting.
Your video shows someone with a lot of experience. Thumbs up.
Thank you the educational video. We just had a power outage in my area and my hvac just stop working the next day. I called the tech out here and they said many homes are not cooling because of the power outtage. I try to reset it by killing the power for about 20 minutes and turn it back on. No luck. I can trouble shoot hvac in cars and big rigs but hvac in a house is a bit more complicated for me because of the unknown. Theses videos help me out understand and not get electrocuted. Lol.
I just had my capacitor replaced with the AmRad Turbo 200x capacitor. He said that were the best and had a 5 year warranty. American made which I like.
I replaced all my AC capacitors with American made capacitors. That extra $50 you spent to replace all the Capacitors with something quality made will probably save you a service call in the future and extend the life your system.
Capacitors rust and deteriorate over time. Replacing them every 5 to 10 years before they fail is definitely a smart idea. Beats calling for desperate service in August with your wife melting and having to pay whatever they want to unless you want to wait a few days...
I will add to Henry's comment and say it was a well done video. Having been trained in electronics, I can share a little bit more.
First of all, note that "oil filled capacitors" (as those are considered to be) are going to be the first type of capacitor to fail. It's just the nature of the physics behind the makeup of the product. Whatever the cause for the failure, these types are more susceptible to failure. BUT! You can't get another construction type of capacitor that will produce that much capacitance in that size of a package either. They become much larger to match the same capacity. Also they are a very cost savings capacitor as well compared to other construction types of capacitors. These types of capacitors are used in many places. If you have invertors in RVs or solar panels on your place you will have lots of these capacitors. They generically are designed to be good and used for apx. 7-9 years. Other posters below have suggested instead of putting in a 370V unit, find one that is rated for 440V with the same mFD rating. That will indeed help prolong the capacitor life for a lot of the same reasons as shown in the video.
Great information. BTW, ironically these things generally only cost about $10-20 and are often the biggest failure point in AC units. If you know what you are doing to put one in, it might do well to have a spare on hand if your unit is getting above 5 or so years old.
I'm not a HVAC tech, but I changed out my 7 year old cap that had been replaced with a Amrad and also installed a Amrad easy start as preventive maintenance in the central Texas heat on my 13 year old unit. I am replacing the contactor as well which is 13 years old just as preventive measure. That's on my list today.
I'm in South Texas....San Antonio to be exact and the darn near year-round heat is brutal.
I'm also not a HVAC tech and I definitely know my limits and know when to call a professional.
I'm also not a ASE certified mechanic, MECP certified, licensed electrician, plumber nor a computer tech but I do all my own work which is quite satisfying.
It's rare for a Contactor to fail so just skip it and same yourself some time, money, and labor. Sometimes they do fail but very unlikely!
@@dickhertz8103 The OEM contactor was 11 bucks. I have had to replace them before.
This is a good practice, that cap (7 years in service) was well past it's normal useful life, in my experience.
Contactors do wear out as well, depending especially on their quality and proper selection for "wetting" capability, which accounts for contact wear.
Is there a particular brand of capacitor that is better quality and where do you purchase them to have a backup on hand?
I am going to subscribe. This video gives an excellent explanation of testing and why capacitors fail. I am a retired equipment technician and if we had a training officer like this in our company, it would have saved time and effort for our junior techs.
I'm of the opinion that capacitors only fail 30 seconds after you've left a job site. Even though you checked the unit and watched the AC run perfectly for multiple cycles after doing a filter change on a unit for the most pain in the ass customer you know. Because we all know "it was working before you looked at it".
As I tell my customers, "it's like your kitchen light bulb, it was working fine 10 minutes ago, but now it is burned out" They all get it at that point...
Unfortunately, not all tech are as honest as they should be. It's hard to tell the good ones from the bad. Most people assume they are being lied to.
@@ramtek2702 It's funny you say that. Most mechanics are paid by the hour with no commissions or bonuses of any type at least where I'm from. There is absolutely no reason for mechanics to lie to a customer to just sell them parts because there's no insensitive for us to do so and we're usually so incredibly busy and have other calls to get to. The real problem is the lack of qualified mechanics these days has caused a lowering of standards when it comes to hire practices. In the last 10 years or so the industry has been floaded with hacks that just don't know what they're doing and they are "parts chargers" because it's the only way they know who to get something to work.
@@ramtek2702 Your first 2 sentences are correct, but the last sentence is wrong. The majority of homeowners don't know they are being deceived so they continue to trust the dishonest ones until an honest tech tells them how the other guy was cheating them.
@@briangc1972 Also, a good tech worth his/her salt may have to suss out the real truth with customers as they can also lie to a tech, hoping to get away with not having to say, pay much.
How you were able to catch the exact moment of failure is just amazing!
Not really. He mentioned he was heating it later on. Probably just holding a torch or other heating element below it. If you compare the before and after, you can see the label near the bottom has darkened significantly from the heating.
5:50 The energy stored by a capacitor is NOT held on the plates but, rather, in the dielectric in the form of an electrostatic field that causes polarization. This is electrostatic induction. A dielectric, by definition, is an insulator. If the rated working voltage is exceeded, the dielectric is literally pulled apart and the plates will arc as you no longer have a dielectric. When the plates arc, there is a vaporization/heating and that expansion is the physical damage on a electrolytic capacitor's can. Other types of capacitors physically fail in other ways.
7:33 The capacitance is not dropping due to a "foil breakdown". It's the dielectric that is failing which will then lead to plate damage.
7:57 Again, the dielectric is what is damaged by over voltage, not the plates.
8:03 The damage is NOT on the plates, initially, it's from the dielectric failure.
In any event, please don't give electronic/electrical theory explanations if you don't understand it yourself.
Plus, in effect current doesn't actually flow through a capacitor, the changing ac voltage in the circuit makes it work the way it does.
Sorry pal u r only partially correct
Hey, the guy does not understand theory, he's a 'repair tech'. Just a warning, this situation is only going to get worse, MUCH worse. In ten years, nobody will know anything about anything. Good luck solving problems in the future. The complete dumbing down of the population has been successfully completed..
You are absolutely correct. However, as we both know, you will observe plate failure on every failed capacitor. That or a dead short. Which is likely where the idea came from.
The good news is that HVAC techs and Electricians don't have to be electrical engineers. They don't have to know why the formula works, just that it does.
The two things that bug me are the Cap not being rated for the peak voltage, and the fact that formula will change based on 50Hz or 60Hz. There's a decent chance the rating is RMS, but the formula is something that could get people who just go by this video in trouble!
Question for you though. You keep saying it's on the dielectric but isn't the dielectric in this case the (forgive my layman's terms) "big roll of foil" inside the capacitor. If you cut one of those open it's basically a giant roll with 2 thin sheets of foil and something separating them.
What is actually considered the dielectric?
This is awesome. Concise, explains everything, no extraneous commentary or time waste. However, If you began by checking the capacitor and found that it was good, why did it fail? Secondly, when you evaluate a capacitor, how do you know that it will fail? which yours did and you apparently knew it, but what was the indication that it would fail?
See my posts below, he heated it (with a torch?). Please click 'like' on that post so it can stay at the top (when sorted by 'top comments')
SO MANY also have this question. Credit goes to others' answers (replies) below that spotted it before me at 5:42, so I also posted this as a comment instead of a reply, so people can see it without searching and opening all the replies.
Mr KL
Thanks for this, I recently paid a service technician $250 labor to replace my capacitor, it took him about 10 minutes, now I know where it is, what it looks like, how to tell if it's bad, how to turn off the current, and I looked on line and found out where I can buy a spare.
I installed my central A/C in my home myself 24 years ago. I am not a tech, just a DIY type of guy. 5 years ago the condensing unit stalled, I found it sitting there humming and unable to start. A little bit of online digging gave me the answer, and the capacitor had swelling on the top and bottom of the can just like what is shown in this video. I found a replacement cap on amazon for about 15 bucks and bought 2 to have a spare. Up and running in no time for chump change, and the unit is still running strong today, the only other thing I've done is put the gauges on it 2 years ago and top off the refrigerant charge. I talked to a guy who runs an HVAC repair service and told him how I fixed the bad cap for 15 bucks. He said he keeps a stock of those caps on his truck and marks them up to $49.95, and then there's the service call and labor. That's why you pay $250 for the same repair if you call him, and it is totally understandable when you consider his overhead and the fact that he is not in business to break even.
Most semi-densely populated areas have HVAC supply houses where you can buy a cap locally, so have the system back up and running, but if it's not expensive the prudent thing to do is just go ahead and buy one so you have a spare, especially if A/C not working would be a significant hardship on the residents.
After several years it's always a good idea to change out capacitors, contactors and relays, they did their thing, leaving them in is going to take out the larger more expensive components. It's also a good idea to go through a unit and get a baseline on everything for future comparison, no one does this, but most HVACR equipment comes from the factory with a start up check list in the installation manual.
FINALLY someone that understands 'baseline' s.
I heard a lot of posible causes and personally the one thing I’ve been seeing over some years it’s that when you expose the capacitor to extended heat streaks periods,confined spaces(with poor ventilation)and/or very exposed areas to direct sunlight(no shade from sunrise to sunset),the “uf”rating diminishes dramatically compared to systems in well ventilated areas with some shade at least some time of the day!
Maybe you should try out a test like the “Project Farm”guy and let us know how it goes…
The capacitors installed upside-down seem to fail a lot, and they don't bubble up
@@aberobinson1 I’ve never seen a capacitor installed upside down,it’s there a specific brand that do that on their systems,or is it simply a “SPECIAL TECHNICAL CONFIGURATION” that some pseudo-technicians use?
I have seen them horizontal but never upside down!
The upside-down capacitors were installed like that at the factory. I believe on Carrier ICP low-end stuff like air-quest
I’ll keep an eye out since I’m yet to see one. Today I took apart an old carrier condenser with huge capacitors (volume,not micro-farads) and they seem to be the original ones from when it was built,nobody ever laid hands on it since installed(and it was working well but customer decided it was time for replacement),seems that planned obsolescence it’s the name of the game now days,or as some call it “job security”…
@@aberobinson1 also pentair heat pumps
Mounted upside down right above the contactor
Dumb so they can fail and take out the contactor too
Maybe even catch the oil on fire
Wow, you can see the bottom of that capacitor where the label is burn up. They might not all fail like this, but that really helps identify a bad one!
Please share your thoughts on these four topics.
1. Adding surge protector to outside unit. We live in Tampa, the US lighting capitol.
2. Adding a "slow start" device to the unit.
3. Using Turbo 200 Motor Run Capacitor (made in USA). These have 5 year guarantee.
4. DIYer changing Capacitor.
Thanks -- great video.
Another reason for a capacitor to fail very quickly is a brushed motor with worn brushes. The arcing wreaks havoc on the cap.
yep, high current pulses
My brother in UEI arms! Finally, someone besides me! Nice video!
UEI is the best. I've only ever had 3 meters in my 20+ year career, all of them UEI and they all still work. I even dropped one off a roof once and it's still going. I see guys with the Fluke meters that cost double what I pay for my meter that does half of what my DL389+ does, I think that's the model number. Great meters.
Great video… very educational. I have spare capacitors for my furnace but never thought to get them for the compressor. I will be doing that this week. My furnace and ac unit are only 10 years old and the furnace has had one of the capacitors replaced twice.
Thanks.
Yeah better get that one too! Its time.
My AC guy talked me through replacing mine, I always have a spare. Save yourself big money on a service call.
Thank you for all the hard work shooting the video!
Thank you Robert!
Hi I loved this video and especially your maths explanations.
However there was one crucial piece of context that, while obvious to yourself and perhaps most of your viewers here, it initially left me confused. I"m like, this man's a magician, what spider senses is he utilising to know that a cap which he just demonstrated is good (and not just good but good under load!) is going to fail (and pretty soon!) =D
The cause is that when you show your timelapse awaiting the capacitor to fail the vision is zoomed in and there's no visible sign of you presumably blowtorching the cap (also you didn't say how you were going to fail the cap).It wasn't until I rewound this once or twice that I realised there was browning of the label on the capacitor and that you must be applying heat.
It's dead obvious to me now of course! but on first viewing that omission was confusing.
It reminded me of one of my favourite lecturers who, on occassion, would confuse the heck out of us because he'd missed a small piece of important context.
So many thanks for a video that I did subsequently follow, I'm only commenting to help and not criticism. Cheers!
Why didn't he mention the blow torching in the video??
@@TheMatsushitaMan he kind of did, 5:40, "while I was breaking the capacitor with high heat applied to the base of the capacitor".
I wondered the same thing as you did and came to the same conclusion. I specifically read the comments for this reason. Thanks!
@@DaddyBeanDaddyBean I appreciate your 5:40 and yet it also supports that context was missing because the failure timelapse starts much earlier around 2:38 (I started rewinding long before 5:40 trying to figure out the context). I guess I'm trying to say that this is about teaching being hard because as the teacher you're conveying information on a subject that you're already intimately familiar with and its hard to notice if a part of your teaching has unintentionally glossed over something that sets up the context for understanding.
Its also ironic that his diligence in proving that not only did the capacitor get tested as proven working, but also proven working under load added further to my confusion of why it failed so quickly. I in the audience couldn't anticipate how this perfectly load tested cap was going to predictably fail (for example, perhaps he'd run it over-voltage in preparation for this demonstration).
So please know I'm not crucifying him for a mistake, I'm reflecting on the challenges we have in teaching where we are fully aware of the context of what we're teaching and inadvertantly because of that familiarity not realise we've skipped over something that is foundational. I find it fascinating. Cheers!
You dont need a torch, just a hot air gun over 100C.
Thanks for the great lesson. I have also replaced many capacitors after a hard freeze. I had come to the conclusion that the cold will kill them also.
On ACs when summer comes? or heat pumps? If heat pumps, I would guess not the cold itself, but higher start currents in the extreme cold? (or failed crankcase heaters?)
Mr KL
Overheating seems like an easy fix for the design team. If only there was a nice big fan with high air flow just mm away from the capacitor that could be redirected to help cool the capacitors?
could be an option
Ha ha do you want these things to last forever ha ha you have to build in obsolescence and work security
@@shockingguy join to my ass what it has to do with my comment ?
Very informative video. Was disappointed that you did not explain what could be done to prevent a failure or extend the life if that's possible.
Some say that if you raise the capacitor can's voltage (like 370 VAC); will damage the compressor. Not so...
The voltage on the can; is only the limit the capacitor can take. So IF you increase the capacitors voltage on the can; it will NOT hurt the cap nor the compressor at all. But if you lower that voltage; that's another thing.
So many techs replace the 370 vac to 440 vac or even 600 vac, etc volts. And they say it lasts much longer. I believe that; as having been an Electronic Tech for TV's Radio's and even AC's; for 45 yrs. Retired in 1996.
For what it's worth.
So, what is the reason for making a 370 vac capacitor??
TL;DW
1. Capacitor is too hot; unit is in the sun or just is hot a lot.
2. Capacitors are expendable items. Hotter they run, the less they live.
3. Voltage spike, e.g. surge, lightning strike, etc.
4. Bad connection point overheats terminal and creates a failure.
The best way to keep your air conditioner running is to have this guy come out right BEFORE the cap fails - because he knows exactly when that's going to happen!
He made it fail by putting a torch 🔥 to it.
When we hit 90 plus here in nc, that “torch” still makes them pop
Great video! I’m sitting here in the Florida Summer heat waiting for a new AC. Going to be a Carrier heat pump. My Trane lasted 19 years with the usual TLC. Evaporator coil sprung a leak. It was a straight cool with gas heater.
Dielectric fluid main purpose is not specifically a cooling fluid. Its main purpose is to prevent conduction between plates of the capacitor. Lower powered capacitors use air as a dielectric. As with many fluids there is a cooling side effect
With DC current the dielectric does not allow current to pass between plates and one plate will hold the charge for a very long time. This can also be very dangerous for those larger capacitors if they are assumed to be discharged you can get quite a big surprise if in stead they have a charge in the capacitor. I learned long ago like a gun do not assume the capacitor is discharged. Always discharge them by shorting the leads at least 3 times. When shorting the leads it will only discharge 1/3 of the charge at a time. Yes there will still be 1/3 of 1/3 of 1/3 of the charge left in the capacitor but at this point it is generally considered safe.
When using AC current there is a charge then a discharge effect for every cycle there for creating the appearance of electrical transference. Its actually capacitive reactance. When coupled with an inductive motor it causes a phase shift to help push the motor through its magnetic phases. The explanation is more complex than I have time but do some googleing and you will find how that works I am sure.
I had always discharged them with a screwdriver. It was almost always uneventful, except one time I was in an older type of development, and when I discharged the cap it went off like a gun shot, echoing through the neighborhood for a few seconds afterward. I was sure the cops would show up, though they never did. I wouldn't have wanted that jolt to go through me, that's for sure.
And critters laying across the top of your capacitors. Excellent video well done.
Why aren't the units designed to cool the capacitor using airflow?
Why aren't there heatsinks/fins on the capacitors? (especially with cooling airflow)
In many devices, these cooling methods are applied to other electronics parts sensitive to heating so why design them such that the capacitors fail earlier than they have to?
It's connected physically to the rest of the unit so whatever heat is in it is going to get shared with the rest of the thing. And since they're $15 on amazon I'd guess a separate cooling system would be more trouble and expense than it's worth.
Because that would cost more and these days things are engineered to just last past the warranty, on average. Besides the idea is, a capacitor is inexpensive to replace, and not even soldered into the circuit. That is, until a pro tech makes his living doing it, lol.
As far as other devices, very few non-commercial electronic devices use any kind of additional cooling measures for the capacitors, unless you just consider it a side effect of proximity if the caps happened to be in a fan cooled power supply where the fan's primary purpose was keeping other things cool like transistors and diodes.
It is called planned obsolescence. If the AC unit lasted 30 years, the manufactures wouldn't have future business. Watch the video on light bulbs. The companies agreed on life hours for the bulbs. Wake up to the intended failures built in to everything you buy, so you will need a new one. Cell phones are a prime example. Yes, there are technology limits to some things.
for increased profit. Why isn't your ac built to last 50 years. Why do they corrode out. Reduced cost, earlier fail, higher profit.
@chuck 8094 How about installing a muffin fan to blow air across the capacitor? Been retired 20 plus years but remember using slip-on fins on capacitors; do not know if the fins are still made but they help a great deal.
Thanks for excellent post. Truth is the replacement caps are so cheap I just replace them every spring
Is overheating a large reason for capacitor failure? If so, could cooling fins or heat sinks be part of a solution?
The solution?? The very simple is when motor start or stop, it generates a spike volt 370V x2 ~ 740V. So then it required as least 800V or 4 cap which is 2 in parallel and 2 in series. Moreover it also required a snubber for AC not DC diagram to protect and return these higher volt if the coil did.
P/s: Also the vibra will make the statistics R then a dielectric grease and stronger contact from wire to cap.
Yes, increasing surface area of the cap can, or what it's thermally coupled with, will tend to increase lifespan, but it would cost the manufacturer money to do it and from an end user perspective, rigging that up might be more trouble than it's worth compared to just having another capacitor in stock and ready to install.
yes, especially electrolytic types, their life is rated according to max voltage, temperature and ripple current, any reduction of them increases life, in theory a plastic dielectric cap , especially small coupler or decoupler should last forever, if not used!, but if used within limits, plus a safety margin, still almost indefinite, these power start/run ones are a bit different due to various stresses on them
New subscriber and thanks for the education sir! I just had one fail on my 6 year old Carrier unit and it looked practically brand new, no rust or bulging. Put the multi meter on it and it was dead. Replace with a new American made capacitor and we are good to go!
I actually had one fail on me a couple days ago while I was standing there. No Cool call. Disconnect was bypassed. Once I found no power to outdoor unit and disconnect bypassed I went ahead and checked the capacitor and contactor/wiring. Then went over and flipped the breaker. Unit started up and ran normally. There was numerous trade businesses there on a remodel and the breaker was turned off not tripped. So I'm standing there watching system for a couple minutes and fan starts making a terrible noise. Go to check it when I noticed that capacitor popped. All in a matter of about 3 minutes. Tested close to perfect and then popped after 3 minutes of run time. Replaced it, ran it through some checks, didn't find anything else wrong with the system that would cause the issue. Condenser in the shade on an 85* day.....
They can pop a long way with the covers off Found the insides around 4 meters away one day walking up to a motor.
Yep, lucky it failed while you were still there. I'm inclined to say caps are consumable items that should be replaced periodically before they fail, based on age. After a few years is reasonable, IMO, despite they test good and work fine.
@@thisisyourcaptainspeaking2259 I treat contactors and capacitors like the points and condenser on a 1960s Chevy tuneup.
Great explanation. I have replaced my AC capacitor twice now in the almost eight years I have owned my home. In both cases the capacitor was visibly expanded at the end.
for your information if it didn't expand, it would explode.
Explain why capacitors from the 1980’s & older always test perfect every time and never go bad.
Other than the obvious “higher quality materials used”
Replaced my old systems 11 years ago. They had been installed in 1965 and kept their original capacitors. They were in a well-shaded area with free air movement.
Capacitors in 1979 and older contained PCB's which made them last longer. PCB was banned in 1979.
@@joecooksey4331 Yup. Unfortunately they were probably in a lot of the fish I caught in the summer.
@@joecooksey4331 Great point. When I read about PCBs, I soon understood why they banned them. Same with R-12. Without the ozone layer, we would soon all starve. Earth would look like Mars, only with water.
PCBs
I keep finding the Geico lizard's mummified body across the cap's terminals here in Louisiana... The lizard jerky is hygroscopic and absorbs water in very humid conditions and begins conducting again. Over & over.
People should just add a small computer fan at the base of the capacitor to keep it cool wouldn’t this extend its life ?
I liked how, if you watched the decal on the cap, you could see it turning brown from heat way before it actually mushroomed.
I’ve upgraded and installed Flux capacitors on my AC. Now my air conditioner is also my air conditioners own grandpa.
Very nice video! I now know why my capacitor failed. Replaced it and the AC is working again. But at 24 years old I need a new furnace and AC.