Residential Low Voltage HVAC Troubleshooting Class P1
ฝัง
- เผยแพร่เมื่อ 24 ก.ค. 2021
- In this class, Bryan teaches the Kalos techs about Residential Low Voltage HVAC Troubleshooting. Low-voltage electrical operations confuse quite a few technicians, so Bryan covers basic circuits and clears up some misconceptions about the terminology we use.
Circuit boards seem to trip up a lot of techs. Unfortunately, every circuit board has a different configuration, so it is difficult to teach the topic from a general angle. Instead, we can isolate the circuits and functions of a circuit board. Then, we can explain how those fit into the basics of electronic applications.
Techs will get a solid understanding of a system’s electronics by learning about the sequence of operation. Each system has specific terminal designations, and the tech should know what all of those are for. For example, the Y circuit on a split-cooling system energizes a contactor and is associated with the compressor and cooling. On a two-stage residential split-cooling system, both Y1 and Y2 must be energized for the system to function at full capacity.
However, the Y circuit is not necessarily associated with cooling on a heat pump system. So, saying that the “cooling call” is on the Y circuit is NOT accurate for all systems. During a cooling call on a heat pump system, you must energize O (usually orange) to enter cooling mode.
Consequently, memorizing circuit boards and electronic applications can be difficult for technicians who rely on memorization and don’t have a solid grasp of theory. Techs can, however, memorize the four basic components of the refrigeration cycle (evaporator, compressor, condenser, metering device) and the basic circuits on the low-voltage side for heat pumps and straight-cool systems.
Even though we say that many electrical failures are “shorts,” not many people know the true meaning of the term. A short happens when a circuit takes an unintended path. To diagnose a short, you have to know the intended path and see where the circuit tried to take a shortcut and bypass the load.
When the current bypasses the load, it experiences little to no resistance. Blown fuses and tripped breakers on the transformer indicate shorts. A fuse blows when too many electrons flow through it (the current is too high).
Another type of short that doesn’t involve a blown fuse. When wires rub out, the current may bypass the switch but not the load. We can refer to these as “switch-leg shorts.”
We also tend to misuse or overuse the word “common.” “Common” merely refers to a place where you connect things together. For example, the C terminal on a capacitor is the common point between two capacitors. On your compressor, the common terminal is the common point between the two windings (run and start). On a low-voltage circuit, common is the opposite of the hot side (24v); common if often connected to ground.
“Open” refers to a break in a path that may be designed or undesigned. For example, an open switch is designed; when a switch is opened, the electron flow stops. So, electricity stops flowing through the circuit, and the system components on the circuit shut off.
When using a multimeter, it is a good idea to set your meter on the ohm scale first. Voltage goes to the leads and will start looking for a path, so you can test your leads by putting them together. When using the ohm scale, make sure you differentiate between no ohms and infinite ohms. You can also test your multimeter by setting it to the volt scale and testing the leads on a known power source, such as an outlet.
As always, wear safety glasses when working on live circuits.
Check out TY's video on Analogies for Magnetism here:
• Analogies for Magnetis...
Read all the tech tips, take the quizzes, and find our handy calculators at www.hvacrschool.com/.
These are the most valuable videos on TH-cam to date for hvac technicians
There are better videos for novices, so it might be for professionals only. Some of the things were over-explained and some were assumed to be known.
@@wortexinternational2598 This is pretty basic knowledge lol
@@wortexinternational2598whatever dude
Look i just got to say. I love your videos they have given me a advantage in class i am a student at ptc. In HVACR. And because i am a girl everyone in the beginning of class was looking at me like i was going to fail. But watching the content you have provided not only have i learned i am the only one making a 4.0 and i am the only one who passed my Universal epa. In fact now they look to me for answers..and my instructor asked me the other day if i was pranking him because i was doing so good in class he thought i was already in this field..so keep on putting out these great videos i enjoy them and its making me look good i forgot to mention i do have a residential electrical degree..but they do not know it because i have not told them..i dont want to intimidate the boys..
Don't pay any attention to what anyone says you can do I had they same circumstances we had a girl in our and she graduated 😊God bless you and keep your head up and keep going 😃
I’m also in HVACR! I’m also female and I’m curious as to what job and who would even hire me in my area. I’ve applied to places and got nowhere. I still plan to graduate and move one day if an opportunity is truly worth my while.😊
That's soo cool
Sounds like you're intimidating them already 👌🏽🩶
@@RubenGonzalez-dd6nu😂😂😂 so true
You're the man. I'm an electrician, I started in HVAC as a sheet metal fab worker. I can always remember, no matter what trade I was working, listening to my predecessors throw out electrical jargon like it was lamens terms. Like, "duh. You got got a open neutral on the load side of the flux capacitor...." And the reality is, that they just understood the technical way to install or fix something based on what it ought to be doing. They couldn't really explain why what's supposed to be happening. I've always wanted the "furthering education" at the companies I've worked for.... And they seldom do any of it. From time to time, they might send a handful of guys to an automation course or something. If this is how you train your guys BRAVO.
As a mid level tech (8years exp.)I think you hit the nail on the head.Sometimes as technicians we complicate things further.I’ve been watching sequence of operation by you and Already this week it has cut my troubleshooting time down.Instead of guessing you go thru the steps of operation and BOOM there’s your problem.THANK YOU #blackICE
I do the same thing Brian, i pick a random person every day and hold up a marker. They all know i want them to go to the board and draw out the refrigeration cycle, HPHTV , HPHTL , LPLTL/M , LPLTV along with SH , SC and where it happens in each component. Love your vids man.
Great class , thank you Brian and Kalos! Such valuable info, whether a refresher or just starting out. Never too old to learn👍🏻
This helped me out alot, will be watching again and looking forward to part two
Trying to maintain my residential heat pump w/o prior hvac knowledge. Learning from scratch. I've learned enough so far to at least know when I must stop and call a pro
Make sure even when the power is off if you have a capacitor issue which usually is the first to go that you discharge it with a screw driver. Run the screw driver across the terminals or else your in for a rude awakening. But yeah good luck
Never too late to get into the game sir! If you’re gonna learn ya might as well get paid right?
And its good to learn because you will know the difference between a pro and an amateur
Outstanding presentation, thanks will watch again and again!
You are a motivation I’m a lead in Tampa go because of you thank you !!! One day I will be at kalos!!! Keep making vids!!!
A really good video, you remind me of my Hvac teacher at Eastwick College in Nutley New Jersey Gary Bliss very knowledgeable. I really appreciate you
Awesome video Bryan.! I’m a year into my schooling and all your videos have really helped me build my knowledge.
This TH-cam channel always makes the best content hands down
Wow! Refreshing my brain after almost 6 years of not touching Air con. Very helpful. Thanks.
Great over view, easy to follow and interesting instructor. Always good to review the meter EVER TIME. Thanks.
Awesome channel! Thanks much! glad I subscribed. I went to a 9 month trade school course and I SO WISH CLASS sessions were some what like, This!!! I'm staying tuned. 📺. Truley learning from the best!👊🏼🤙
Great content I learned a lot from this video very grateful for your heart you have for this trade and your willingness to teach with amazing attention to detail. I hope to be as wise as you or even 60% lol but I really want to be the best at what I do. Watching your videos helps me very much
You are right about doing much with boards. After my defrost board needed replacing and I couldn't find much info on it or boards in general, I bought one to see how it worked. It had adaptive demand defrost. General rule are the 24 vac power gets rectified to a 24v DC rail (the relays will have coil voltages of around 22v DC) then a microcontroller, running a program you can only guess at ,switches the relays via transistors. A lot of the sea of resistors and diodes/capacitors are modifying the 24vac signals so the micocontroller can read them. As for mine with ADD, another 5v DC rail which powered a ubiquitous PIC m-controller as well as the ambient and coil thermistors. Not a lot to test in the field without risking a short circuit or something besides signal input, output. Would be nice to have a good procedure to test thermistors. But even then, it is unlikely you could easily test for drift in the thermistor. So a temp reading is only marginally useful. Mostly it would be open or shorted.
Then the future is more complex boards with tiny surface mount components. Without test ports and procedures by the manufacturer, not much you can do in the field or without a microscope.
Thanks for sharing your knowledge.
Thank you for all videos & advise👍🏼
this is top notch content. thanks.
Bryan, you are a homie. Much love
Great information for real applications in field
this is a great presentation, keep it coming
Wow World Class Training
Good class great explaining
Excellent video thanks
very nice sir..and a lot of thanks to you for sharing with us...
Great class, 👍👍
Ready for part2 already
Better training then my school offer .
Great video.
Awesome video!
Thank you.
Love it this videos help a ton. :)
MAN I NEEDED THIS
Love your videos when are you going to do a book on troubleshooting. Thanks for the videos.
Great video
Short to power - unintended touching of two wires on the positive side of the load.
Short to common - (in automotive short to ground) - unintended touching of wire on positive side of a load with the common wire/chassis (sometimes called ground).
Common is a return path from a load to the power source (transformer) that by convention does not have any switches installed between it and the "negative" side of the power source. Thus, it is a a a logical busbar connected directly to the return (negative) side of the power supply. Common can be and, is in mains power distribution almost always, bonded to the system ground which makes it a neutral or a wire with no/very low potential difference between it and the earth ground. In HVAC, common may be "grounded" by bonding it (screwing it down) to the chassis of the cabinet. If the low voltage common is bonded to the chassis of a properly installed blower cabinet, it will then be bonded to all grounded chassis elsewhere in the building, including a properly mains wiring grounded outdoor unit. In automotive power electrical, all metal parts of the car, motor, frame, body is commoned to the negative battery terminal, and is called "ground". So any power wire (power of high side of the load) touching a metal part will cause a short to common/ground.
Wow thank you
Great Video, Thanks you🙏🏼 HVAC School.
thank you very much !!!
As a sparky.... LDL when testing at least the initial use of the meter. It gets old quick but Live, DEAD, LIve is check known good circuit/proving box, remove power check for dead, then power up and check again. Just to make sure your meter is working, should do the same with non contact (hot stick) too. We all have trusted a hot stick and then hucked it accross the job when it failed. I know its a PITA and no I do not do it all the time either but as I have gotten older I do it MUCH more often ELECTRICITY FLOCKING HURTS.
this is amazing
I had a short one time in an old house where everytime I would touch the handle for the hot water I would get a jolt. I turned the breakers off one at a time until it stopped doing it and I found a neutral wire loose in a light fixture in a bedroom. The current had found a path to ground through a water pipe some kind of way. Everything worked fine as long as you didn't stand in water and touch the hot water valve.
Thank you,
Thank you
I would say it is good to teach new guys that our meter is a difference of potential device, phase to ground vs phase to phase, theory on the fact that 0 volts between leads means there IS voltage present. Most all apprentices that I get aren't taught this value multimeter piece of theory. Good LV content on this video. I have wondered, what is a good rule of thumb resistance value across contactor coil. I've had multiple calls, finding fuse blowing only after a call for cooling. Coil resistance less than 8 ohms usually the problem. Thanks
Yes this guy is a good instructor. What school is this? I did auto/diesel at UTI in sacramento and those instructors too are great. This was a great refresher video. Thank you!
If I were a younger man, I would come to Florida to take your course!
great tech school
Nice video
Short= path to ground Common = Shared
you guys rock
havent watched the whole video yet but i will ,,,,from the top of my head as far as circuit boards we where told in class ,,,,if you have voltage to it and not out of it ,,,its a bad board ! now lets see the vid here ,,,,,
I always enjoy Bryan's videos. I used to listen his HVAC podcast a lot back in 2018 - 2019. but then I stopped watching his videos because I got into Appliances repair. i just came across this video. I see that he's still teaching simple concepts. are these students new?
I’m sure it’s a training class for his somewhat new techs for their specific industry and company.
very good sir
I finished HVAC school this summer, would you guys say that this is a good re-sharpening tool as I get ready to acclimate to the field?
i'd love to see mechanical problems on the board like what I endure at my school. Where you are given low side pressure, hi side pressure, ambient temp, and a few more and then are told to calc evap split, cond split, subcool, superheat and tell instructor what the problem with the unit is. Otherwise could you tell me where I can find such videos. thanks.
I have repaired circuit boards in the field.
Talk about abcd infinity thermostat, how to change it to conventional gas furnace??
Hi. Can you please make a video of the proper way to flush a line set from r22 to 410a. The system is in a condo and is imposible to replace it. Thanks
At 7: 32. Where is this "racked manual" online to buy or read. Google didn't pinpoint it on my end.
I like the guy with the crocks/socks combo at work
I'm using TH-cam to straighten out my HVAC that a tech screwed up and it's a good chance he learned on your video.
Doubtful
If thermostat short will cause fuse blowing fuse in control board
Bryon, pcb's àre nothing more than..1) a split portion of the devices on the unit we service, and..
2) a combination of timers and switches with some adding an ignition section. Pin in and out connectors vary by brand. You make an awesome instructor, I would work for you in a heartbeat.
👍🏼
Hi could you please explain something to me. I have just seen a video where it is stated that a PTC is connected to the compressor and not a BiMetal cut out. Surely it can not be a PTC?
When you close a door, you complete a line. The wall is the line.
Not bad, I feel watching Bryan ask other people questions... I don't know I just got lost with this one.
I could have saved myself 24k and just watch these videos instead
Lmao church bro. I'm a service tech self taught hvac vids n on the job training. However them nate certs look good on a resume.
You are in Arizona because you said Ron.
What company do you work for?
Any cliff notes or a summary?
Short to ground vs short to common?
Free education, Go 🇺🇸.
I’m a novice, that has dealt with 100’s of Goodman residential heat pumps and I really don’t understand why a heat pumps can’t have models with option of reversing valve solenoid having cooling mode default- configured so without the twenty four volts we have cooling and need solenoid energized for heating? In the southern states cooling is more important and most heat pumps have heat strips that are more then capable of heating without the heat pump.
Unit would be more efficient and use less energy ( be more green).
it may have to do with pipes freezing if the heat fails and the heat pump can go to emergency heat. if the A/C fails you don't have emergency A/C.
@@caru3257 thanks for the input, but I don’t think so. Not arguing, just still doesn’t make sense to “ me”. Cheers
Reem
How do those twitchy/fidgety people in the front not bother you?
Good class do you hire 69yo rookies?
Two hot wires touching would cause a backfeed situation
And I believe I ran into that a few weeks ago. I would have 24 volts outside and then a few mins later I wouldn’t. And wires were shorted 🤣
7:33 he says if you haven’t read the rack manual… what is the right spelling for the rack manual? Thank you I want to read it.
RACT... Refrigeration & AC Technology
Common is return path without common there is no path no current !
Can be hvac translate to speaking of indonesia
Common is neutral
God and Bryon
I still don’t understand ground vs neutral
Check out you tube basic AC explained. Alternating Current is a sign wave, traveling both directions of current flow. N, neutral is a reference point in circuit, a return path for unused voltage back to AC power supply. Ground is grounded conductor, attached tho multiple electrical devices, intended as a conductor to send unwanted voltage to ground, to prevent unwanted voltage from harming equipment or more importantly humans. Grounded conductor N, vs grounding conductor, Ground,,,, this is a confusing topic for sure. As is the term Common. Common hot, common ground, common side of transformer..... on and on.
Just dig in friend, it's all pure freakin magic
Short energized circuit going to ground too much amps
Idk how you have time to do these videos and run a business. I barely have enough time to watch all your videos! Lol
70% of ng furnace issues are related to installation.
🍺🤓👍🏻
Stay safe.
Retired (werk'n)keyboard super tech. Wear your safety glasses.
This is very basic stuff. I guess i thing everyone already knows about.
1st time I ever saw Bryan Orr with hair. Ouch.
does this dude like hearing himself talk? lol
🔰🇺🇸 - Ah…you just t-shoot to board level by process of elimination and if needed just change the board.
Your information is great but you talk too much. Just get to the point. I spend more time fast forwarding your videos than enjoying your videos.
I'm sorry you didn't get what you paid for. I will make sure I perform up to your expectations from now on as your opinions are highly valued.
UNBELIEVABLY painful to watch and hear
This teaching method and class interaction sucked on a galactic level
Please forgive me for wasting your valuable time
Thank you