I subscribed to this channel because as a restaurant owner , I’ve been taken advantage of 4-6 times over the course of 4 years between my walk in cooler and freezer , ice maker and main ac unit. I now carry my own gauges and temp probes to sadly check their work. I video and picture log all my equipment to make sure they don’t “ break “ something they should be doing . I constantly ask the tech questions and their approach and results they are aiming for to verify. I collect their answers and back research info from your channel . Thanks for these videos. They are less inclined to pull a scam on me now .
I am not a tech but I love learning about many things. Having a good A/C tech is important. More importantly someone who is trustworthy. I will continue to watch his videos. Thank you for your knowledge.
I watch Brian to sharpen my understanding of refrigeration as it relates to automotive air conditioning. What a great teacher and orator. Thank you Brian for doing what you do...
Thanks- lots of insights that are new to me. The review of the complete diagnosing procedure was also helpful. One service manager told that first thing he would do was to put his amp probe on outdoors to get an idea about how much refrigerant charge is in the system and to see if the compressor was running. I used that idea to check a new refrigerator at my apartment which was icing up constantly. The store technicians came and told me that it was improperly sloped and not draining & that’s why it was freezing. How ever it continued to freeze up. It was only drawing about 2 amps instead of the rated 6 amps under full load. They eventually replaced that new unit with another new refrigerator. I don’t understand why it makes a loud clicking noise every time the compressor starts up that is coming from inside the cabinet and not down at the compressor.
My friend is taking night classes in south Florida. The instructors first language isn’t English. Poor kid can understand half of what the teacher says. I wish he had you. You are an excellent instructor.
My teacher of the day! I have unlearned and re-learned a few things from your video. Thank you for the wonderful session. You added a fourth angle to my triangle.
I’ve changed power heads before only to find that the valve was restricted at the body, I’d rather just change the whole thing if time and conditions permit. Good class!
We have a Lennox unit that takes 29lbs of refrigerant and it worked perfectly fine in second stage but we were getting the typical readings of a txv valve failure, low suction. I traced the line to the condenser and saw a hell of a mess of a braising job. Traced the TXV and saw that someone had melted the copper with the torch and the pipe was pinched to the point of no airflow when tested with nitrogen. Pointed it out to the Linux tech who recommended we change the solenoid first. We changed the TXV and braised everything. Pressure tested it over the weekend checked for leaks and recharged it. Works like a charm
23:00 I FEEL VINDICATED. I should save this video for every customer who “just wanted” their 20 year-old, never maintained attic AC in their 120 year old house “fixed” instead of replaced.
I just replaced a txv yesterday. It had low suction pressure about 50 psig ( R22) SH was about 45 deg. high head pressure at 400 this was after the day shift added 22. SC way high. Took some out until suction pressure started going down. then pumped unit down, couldn't get low side below 40 psig before the compressors internal bypass opened. The head pressure got all the way down to almost 0 psig. the coil was freezing up. Put the new one in and was getting the perfect cycle. Good feeling!
Awesome video. From my experience with txv is I always see the outlet of the valve with frost build up and my subcool doesn’t make since or is way to high. I know so many installers who braze with out nitrogen and years down the road this is then end result. Honestly on all my service calls are maintenance I always check for dirty indoor coils , filters, ductwork and blower wheels that will cause low air flow. God bless
I purged with nitrogen on all of the systems I’ve installed in the last 20 years. I still have lots of TXV failures. They are junk, engineering in the USA and poorly made in China. Greedy corporations don’t have any problem paying their suits millions.
A note on your statement at the end about what happens if a valve core is left in the port the equalizer line connect so. On many valves, there is not a perfect seal around the rods the diaphragm pushes on to drive the valve open, so refrigerant inside the valve can leak through and push the valve closed. It will be higher pressure than the refrigerant in the evaporator coil, and has no place to go, so will force the valve too far closed. I ran into it a few times back when AS/Trane switched to providing aluminum replacement coils for their air handlers with copper coils. The coils come with no TXV, so you have to field install it, and people were not pulling the valve core out of the port. After starting the system up, the valve would start off forced wide open, flooding the coil, then slowly close down until the superheat was way too high.
REALLY appreciate your explanation about how a restriction can actually show lower high side pressure-- as a refrigeration guy I see that all the time on LG fridges with partial cap tube restrictions.
Constant super heat valve is accurate. Easiest way to check valve is measure superheat and subcool when close to or at temp. Always measure suction temp closest to TXV sensor bulb to calculate superheat. TXV, EXV, DTC valves are fun!
Really good lesson or over view. I’m recommending this lesson to the green hvac bros coming into our co. This will make a good tech out of the average tech filter changers and part changers
It’s a good idea to install a 1/4” flare T at the connection for the equalizer line at the evaporator. The extra port can be used to get a pressure measurement for the actual evaporator pressure at the tail coil, where the bulb is located. This is the proper place to read suction pressure when calculating evaporator superheat
I am currently pretty hungover and I can’t sleep. But I just watched your video and I understood all of the information. Wow. Such a great video, I had to subscribe. I will watch again when not hungover to make sure I retain everything. Thanks so much. Great job.
I guess this should go without saying but I would make sure all of the filters are clean, no slipping belt if there is one, make sure the coils are clean, in this case especially the evaporator coil, CHECK to make sure ALL dampers, diffusers, registers are open and confirm airflow. You would be surprised how many people close registers in a room not used or simply because they don't like to feel a cold draft. You can usually tell when there is a restriction or a bad txv because most times your superheat will be high. And contrary to what some people believe...if you have clean filters, coils, good airflow, then I would absolutely try warming up the txv bulb to see if there is any change in pressure at all...it's a lot easier to do than recovering the charge and changing the txv. Usually before you even get to that point you can usually find the problem. Check for a rubbed through txv capillary, look for any significant temperature differences across filter driers and watch for freezing at the txv. Finally, check to make sure the thermostat is not set too low (people have a tendency to bury it down low) and test it to make sure it stops and starts the system with reasonable accuracy. A system that runs too cold can log up oil in the evaporator coil and reduce heat transfer. Try shutting the system off for a half hour to let it stabilize and startup with a good heat load. I hope this helps.
Pure gold Bryan, So technical you really drive home the facts, I love the videos and podcasts great reminders to strive for greatness and never assume without having all the facts Thanks again.
Wasn't sure where to ask this question, but I am looking for an electronic expansion valve with a controller that will allow me to run suction pressure below zero PSI. I can't find a controller that won't fault out when trying to run Ultra load temperatures like -80F. I have to put the controller in manual mode then I can dial the electronic expansion valve to exactly what is needed whereas a TXV loses a lot of its ability to meter at these ultra-low temperatures. BTW your channel is in first place tie with the engineering mindset Channel. That's a pretty big compliment
sorry to hear that man you must of worked with some bad guys, i feel the opposite iv learned way more in the field to the point where i dont get much from alot of his videos, not bragging but alot of his material is introduction to stuff and very basic
trebrehenuf .......you’ll learn even more and much faster when you put hands-on. And more still when you’re on your own, with nobody watching you. Also, this is a trade that is very cerebral and you’ll constantly learn. Like the instructor said, even a seasoned tech can misdiagnose.
Thank you I’m working on a unit now that I have to check all this because when I got there it was frozen so I told him I would be back the next day to hook up everything again and run it properly and see what’s going on before I condemn anything
some aircons have check (one way) valves that will give some of the same symptoms as a bad txv. if you are thourough in the diagnosis it will become obvious but always use both hi and lo gauges and check system temps in lots of places. its been rare to have a check valve fail but they can give you a real hard time if your not aware of them.
Brian so instead of running up and down from attic to condenser unit every time you warm or cool the TXV valve bulb what about taking advantage of the Fieldpiece or Testo probes along with the Measure Quick app and watch what you pressure's and temperatures are doing. Saves alot of running around for those that have them or frees up a second person. Also can probably use an infrared terminal immature on the TXV. Just a thought 🤔
Same. Some guys check pressures, SH, SC. Then, put txv bulb in hot water, and recheck those pressures,(suction should go up, feeding more refrigerant) you could also do ice water and txv should feed less and have lower suction. But others check pressures, SH,SC, but they even add refrigerant and see that suction deadends, again to Bryan's point, neither of these are practical. More so checking more things like discharge gas superheat off compressor. I've learned about having bad txv when changing a rusted drier, then added refrigerant charge to unit charging chart then the suction hit a deadend and wouldn't rise anymore upon adding refrigerant, the headpressure would also stack if much more refrigerant is added after that deadend. Not the best way to know, why I've been trying to find better approach.
Maximus Decimus Meridius lies, kink liquid line or clogged filter drier will increase head pressure along with liquid saturation temp which will show a subcool within range, or dirty condenser coil will raise liquid pressure and show subcool within range. Don’t feed false information to newbie techs bud.
Brian, thank you for your time and effort in making great content for us all to learn from. I work on commuter trains . We have 2 , 8 ton package units. In each unit There are 4 TXV's feeding 2 evaporator coils. There is liquid line valve and a branch circuit off the liquid line that incorporates a modulation valve, that when energized provides "Full cooling" capacity through feeding all 4 TXV's. Partial cooling capacity is accomplished by de-energizing the modulation valve and feeding only 2 TXV's . Question, Would I have to operate these units in full cooling to properly calculate SH? I've never seen a system with multiple TXV's like this before. There are no manifold gauge connections, only transducers and NTC thermistors mounted on the liquid and suction lines. We use R-407C refrigerant.
Thank you for this wonderful video.... I understand everything you explain in this video minus one factor. When you have a moment can you kindly explain why your DeltaT will go up when you have a bad TXV. Many thanks
If the TXV is underfeeding, there will be a noticable drop in pressure in the indoor coil. This will cause the coil to significantly drop in temperature. The air being pulled across will lose a lot more heat because of the colder than normal coil. This is what gives you a higher delta T.
It's always taping on the txv the diaphragm with a pen. Then have a new power head and listen to the sound. Push on the diaphragm. You will see the difference. Some alco or sporlan valves willo have a kit at RSD and you don't have to replace valve body. Just make sure it's the right power head. You can use a pressure limiting power head to shut down the system in case of refrigerant lost. Pumping down and pulling a vacuum will allow you to do this.
The video is very informative for technicians who knows all this stuff already. For me who just starting to learn about hvac is a headache listening 10 words in a second . Cutting the video clips to make a shorter video doesn't help me.
Bryan great video as always, but ive always wondered and asked what refrigerant is used inside of a sensing bulb. It would make sense to me that the bulb would have a small amount of liquid refrigerant of whatever the system uses that its rated for but i have never been able to find documentation or get a definitive answer. Just a question ive had for 10 plus years.
Carrier tech support helped me diagnose the txv. Seems like your saying high superheat, low suction pressure, good subcooling is what we are looking for.
I pretty sure this is a class for HVACR technicians Continue Education, but not a class for newbies like me. Will come back after I have certain HVAC knowledge
our teacher who had at the time little over 35 years in the trade told us that 3 degrees in HVAC is close enough and dont sweat it too too much ,,,,just cool that house LOL ,,,,specially in miami /ftlaud / etc southern fl,,,nice show
Thanks Bryan great video technician going possible back into field after 14 years in house maintenance. Probably watch again.Beer can cold days are long over. Thanks got your app on my phone!
I bought a brand new home. 9 months into it, the builder, who is preparing to replace my laminate flooring, takes a picture of my dry mulch and tells me my a/c is broken! I knew my a/c wasn't broken, it was set on 73 and it was 69 in the house, (cold outside and it's been running perfectly, so I told the builder if he thought my a/c was broken, then he'd better call the a/c man. Well, the man came out, didn't speak to me, took both of my units apart, took the txv out, welded, worked on both units for a total of 3 hours jeri-rigged the a/c so it would run at 60 degrees. The 9th day, he came back, spent another 3 hours welding and taking things apart, said he gave me a new txv, and left. No paperwork. I asked him why. He said the txv would have gone out down the road. What? He fixed it before it was broke? Before anything was broke? What was that about?? Thanks for the video!
22 year old Trane R22 system. XE1200 with a TXV on coil. (13 Seer) Condenser coil very clean. Evap coil can't be observed, without cutting case. (Probably dirty, after 22 years.) Outdoor temp 90 degrees. Super Heat is 49. Sub Cooling is 17. (Coil paperwork calls for 16 nominal sub cooling.) Liquid line / head is 210 psi and suction line is 49 psi. Obviously freezes up and looses ability to cool below 74'. Trane factory dryer / filter on condenser does not reflect difference in temps across. Liquid pressure line temp outdoor is 85' indoor is 82'. 25' delta T. Sounds like TXV to me. I will test the TXV bulb by dipping in cooll to hot water and watch the low pressure this week. Feedback welcome!
I feel really smart TH-cam is recommending this to me and I have no idea what the hell this guy is talking about. But everything that breaks gets fixed in my house so I guess one day this video will come in handy!
In easy words, restriction means: a mass flow of refrigerant is flowing inside the pipes very little although you have enough refrigerant level in the system.
one time I suspected a kink and the line temp difference between ID and OD was like 15-20 degrees. I searched and sure enough the lineset was bent where it exited the wall cavity.
Every TXV I have had a problem with was gummed up. Just take it apart and clean it with a brass wire brush and nonclorinated brake parts cleaner. Reassemble evac and dump the charge back in. I replace the filter dryer too when I opened the lineset.
You can also cover the condensing fan or unplug it and watch the head pressure go up and your suction pressure should maintain and not move at all this is a good txv if your suction and liquid line increase bad TXV
I actually check the bulb when I suspect underfeeding. I'm weird. I carry sandpaper in my back-pocket. Why? because it don't hurt. Worst case you wind up with a cleaner copper tube. But even though air-flow is a pretty large and intimidating area of HVAC, you know what isn't? Checking for dirty filters or iced/gunky coils. Takes almost no effort. Video was very informative. I'm a new tech., I try my best to stick to basics....but we tend to panic and check backwards. I have no idea why I do that when i panic. I'll look for the most convoluted problems, but it's rare. It's usually beyond simple. Like bad drain lines, dirty, a loose connections, ect...
I find with most airflow issues the sc will be ok and the suction pressure will be low and the sh will be really low too because thier isn’t enough heat to boil the refrigerant in the evap coil. Not always buy most times that is the case
That does make sense that superheat would be high. I must admit I’m the guy who grabs my tank. If it starts running right, I look for the leak. If the head pressure starts to sky rocket, I’m over charged and have a bad txv. And it seems like a a couple ounces makes a big difference.
Common issue with installers over heating the suction line on units while brazing and burning up the temperature bulb and causing the txv to remain closed. Causing compressor to pull a suction side vacuum.
I’ve been installing high efficiency equipment for 25 years, purging with nitrogen and keeping TXV’s cool while brazing. I’ve had plenty of failures between 4-8 years. Chinese sourced, poor US engineering.
Love the information on all aspects of an air conditioning system. My question is on the TXV bulb does the pig tail " this is what I call it " on a vertical line need to be in the up position and insulated? Thanks for the feedback.
Yes, they're charged with refrigerant, install the small line coming off the bulb up when it's in a vertical position. Horizontal is preferred, just keep the bulb from the bottom of the line. Somewhere between 9 and 3 o'clock.
Speaking so fast it's not enough time to allow for proper understanding of your point. Slow down a bit and allow time to connect the points you're bringing out!
Got some real issue with a chilled water bank system. It's a R22gass system, using ×2 Copland (6.8) hp rottary compressors and 2 TGEX expansion valves the system is a water cooled condenser. Issue here is am getting a very high head pressure even causing the relief valve to engage at 300psi (which it's labled) even besides dropping the gas level to a point were the LP switc (electronic) regards low in sync with my guages low side when I push on the contactor the head pressure doesn't seem to stop rising NOTE this is a brand new system has never worked since purchase date what would be the issue
Great video. Add a hot gas bypass system with liquid quenching to this and troubleshooting gets even more interesting. Then throw in flooded condenser and it's a party.
I always questioned the reasoning behind "clocking the bulb" so it doesn't sense the liquid. Umm, it's at the outlet of the evaporator on a copper tube. Right?
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I've been watching videos of you classes you're very informative I really appreciate the information you guys are awesome
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BILLY ORR! You're the fucking man, bro!!!! You explain in my language. Keep it simple, realistic terms and terminology. Good looking homie
How to know is good fully refrigerant charged walking box freezer and cooler
Very good instructor. I have 45 years experience and 20 of that with Carrier and York. I’m still learning.
I subscribed to this channel because as a restaurant owner , I’ve been taken advantage of 4-6 times over the course of 4 years between my walk in cooler and freezer , ice maker and main ac unit. I now carry my own gauges and temp probes to sadly check their work. I video and picture log all my equipment to make sure they don’t “ break “ something they should be doing . I constantly ask the tech questions and their approach and results they are aiming for to verify. I collect their answers and back research info from your channel . Thanks for these videos. They are less inclined to pull a scam on me now .
I am not a tech but I love learning about many things. Having a good A/C tech is important. More importantly someone who is trustworthy. I will continue to watch his videos. Thank you for your knowledge.
I watch Brian to sharpen my understanding of refrigeration as it relates to automotive air conditioning.
What a great teacher and orator. Thank you Brian for doing what you do...
You getting too long-winded with your explanation’s
This guy is a great instructor. I don't really have that gift. So i appreciate anyone who can instruct/teach/facilitate
Probably one of the best HVAC channels TH-cam
THis is by far the best explained txv operation and fail operation ive seen yet... THank you for the very good lesson
Completely agree!!! 💯
We often use your videos for our weekly training with our techs. This one was great! Thank you again for what you do for the industry.
Thanks- lots of insights that are new to me. The review of the complete diagnosing procedure was also helpful. One service manager told that first thing he would do was to put his amp probe on outdoors to get an idea about how much refrigerant charge is in the system and to see if the compressor was running. I used that idea to check a new refrigerator at my apartment which was icing up constantly. The store technicians came and told me that it was improperly sloped and not draining & that’s why it was freezing. How ever it continued to freeze up. It was only drawing about 2 amps instead of the rated 6 amps under full load. They eventually replaced that new unit with another new refrigerator.
I don’t understand why it makes a loud clicking noise every time the compressor starts up that is coming from inside the cabinet and not down at the compressor.
My friend is taking night classes in south Florida. The instructors first language isn’t English. Poor kid can understand half of what the teacher says. I wish he had you. You are an excellent instructor.
My teacher of the day! I have unlearned and re-learned a few things from your video.
Thank you for the wonderful session. You added a fourth angle to my triangle.
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Great video! Spot on!! The TXV has got to be the most misunderstood component of the trade.
Add air into the mix and you got yourself a long day
This has been a great Lesson and reminder about how to do the job better on properly diagnosing the TXV.
If only they taught me this well ... Fantastic class , sir , I wish I'd had my training with you guys 👍
Been doing service since 87....Love the vids....It is making me a better tech and helps me hone my skills....Thanks.
Excellent Brian ! You can explain the workings of refrigeration parts in an easy to understand way .
I’ve changed power heads before only to find that the valve was restricted at the body, I’d rather just change the whole thing if time and conditions permit. Good class!
Watch this video a couple of times and makes me feel good to get this knowledge about txv
We have a Lennox unit that takes 29lbs of refrigerant and it worked perfectly fine in second stage but we were getting the typical readings of a txv valve failure, low suction. I traced the line to the condenser and saw a hell of a mess of a braising job. Traced the TXV and saw that someone had melted the copper with the torch and the pipe was pinched to the point of no airflow when tested with nitrogen. Pointed it out to the Linux tech who recommended we change the solenoid first. We changed the TXV and braised everything. Pressure tested it over the weekend checked for leaks and recharged it. Works like a charm
calling the TXV a constant superheat valve is a good trick for remembering what it does
Mr. Orr here is what one would call an Hvac God. Love this dude and he has helped me through many a quandary.
23:00
I FEEL VINDICATED.
I should save this video for every customer who “just wanted” their 20 year-old, never maintained attic AC in their 120 year old house “fixed” instead of replaced.
or a crawlspace....
I just replaced a txv yesterday. It had low suction pressure about 50 psig ( R22) SH was about 45 deg. high head pressure at 400 this was after the day shift added 22. SC way high. Took some out until suction pressure started going down. then pumped unit down, couldn't get low side below 40 psig before the compressors internal bypass opened. The head pressure got all the way down to almost 0 psig. the coil was freezing up. Put the new one in and was getting the perfect cycle. Good feeling!
Exactly. Tech knowledge good. Experience is key
Head pressure 0psig?
Billy Monis your over charged! That’s why it won’t pump down. Txv is not your problem
@@ryanjordan6144 if the TXV has been starving the compressor long enough it will go out on high heat when pumping it down. Doesn’t mean overcharged!
Awesome video. From my experience with txv is I always see the outlet of the valve with frost build up and my subcool doesn’t make since or is way to high. I know so many installers who braze with out nitrogen and years down the road this is then end result. Honestly on all my service calls are maintenance I always check for dirty indoor coils , filters, ductwork and blower wheels that will cause low air flow. God bless
great comment, thank you
I purged with nitrogen on all of the systems I’ve installed in the last 20 years. I still have lots of TXV failures. They are junk, engineering in the USA and poorly made in China. Greedy corporations don’t have any problem paying their suits millions.
A note on your statement at the end about what happens if a valve core is left in the port the equalizer line connect so.
On many valves, there is not a perfect seal around the rods the diaphragm pushes on to drive the valve open, so refrigerant inside the valve can leak through and push the valve closed.
It will be higher pressure than the refrigerant in the evaporator coil, and has no place to go, so will force the valve too far closed.
I ran into it a few times back when AS/Trane switched to providing aluminum replacement coils for their air handlers with copper coils.
The coils come with no TXV, so you have to field install it, and people were not pulling the valve core out of the port.
After starting the system up, the valve would start off forced wide open, flooding the coil, then slowly close down until the superheat was way too high.
Great, great class this instructor is an asset to the hvac trade. Good job.
I really miss this instrumental intro to your videos. Please consider using this tune in future videos.
Great instructions on diagnosing a failed TXV
I like the explanation of the bulb being the opening force.👍
REALLY appreciate your explanation about how a restriction can actually show lower high side pressure-- as a refrigeration guy I see that all the time on LG fridges with partial cap tube restrictions.
Constant super heat valve is accurate. Easiest way to check valve is measure superheat and subcool when close to or at temp. Always measure suction temp closest to TXV sensor bulb to calculate superheat. TXV, EXV, DTC valves are fun!
Very informative, I've also been a last resort to change a txv,but over the years have had a few that were the TXV valve was bad..
Really good lesson or over view. I’m recommending this lesson to the green hvac bros coming into our co. This will make a good tech out of the average tech filter changers and part changers
Good video I'll be watching this one a few more times.
he is a very fast talker LOL
I learned a lot from this video that I can use everyday. You are a HVAC wizard.
Great information. I'm new to this stuff, so it was lots of food for my brain. You explained it in a way I could easily understand. Thank you
It’s a good idea to install a 1/4” flare T at the connection for the equalizer line at the evaporator. The extra port can be used to get a pressure measurement for the actual evaporator pressure at the tail coil, where the bulb is located. This is the proper place to read suction pressure when calculating evaporator superheat
I am currently pretty hungover and I can’t sleep. But I just watched your video and I understood all of the information. Wow. Such a great video, I had to subscribe. I will watch again when not hungover to make sure I retain everything. Thanks so much. Great job.
I guess this should go without saying but I would make sure all of the filters are clean, no slipping belt if there is one, make sure the coils are clean, in this case especially the evaporator coil, CHECK to make sure ALL dampers, diffusers, registers are open and confirm airflow. You would be surprised how many people close registers in a room not used or simply because they don't like to feel a cold draft. You can usually tell when there is a restriction or a bad txv because most times your superheat will be high. And contrary to what some people believe...if you have clean filters, coils, good airflow, then I would absolutely try warming up the txv bulb to see if there is any change in pressure at all...it's a lot easier to do than recovering the charge and changing the txv. Usually before you even get to that point you can usually find the problem. Check for a rubbed through txv capillary, look for any significant temperature differences across filter driers and watch for freezing at the txv. Finally, check to make sure the thermostat is not set too low (people have a tendency to bury it down low) and test it to make sure it stops and starts the system with reasonable accuracy. A system that runs too cold can log up oil in the evaporator coil and reduce heat transfer. Try shutting the system off for a half hour to let it stabilize and startup with a good heat load. I hope this helps.
Pure gold Bryan, So technical you really drive home the facts, I love the videos and podcasts great reminders to strive for greatness and never assume without having all the facts Thanks again.
Wasn't sure where to ask this question, but I am looking for an electronic expansion valve with a controller that will allow me to run suction pressure below zero PSI. I can't find a controller that won't fault out when trying to run Ultra load temperatures like -80F. I have to put the controller in manual mode then I can dial the electronic expansion valve to exactly what is needed whereas a TXV loses a lot of its ability to meter at these ultra-low temperatures. BTW your channel is in first place tie with the engineering mindset Channel. That's a pretty big compliment
Txv is pure gut feeling. I change out 9 every summer
Learned more in 30 minutes watching than 2 years working with journeyman.
sorry to hear that man you must of worked with some bad guys, i feel the opposite iv learned way more in the field to the point where i dont get much from alot of his videos, not bragging but alot of his material is introduction to stuff and very basic
trebrehenuf .......you’ll learn even more and much faster when you put hands-on. And more still when you’re on your own, with nobody watching you. Also, this is a trade that is very cerebral and you’ll constantly learn. Like the instructor said, even a seasoned tech can misdiagnose.
The best techs have made the most mistakes.. they learned from them and made themselves better.
Exactly...
Most excellent and informative video with an excellent instructor.....Thank you Testo.
Nice videos...
Can understand how txv works and fails
Please like to my channel also
th-cam.com/channels/VGxieHOcnRHZqMyC8ZrWtw.html
This is solid information. Presented and spoken well. Awesome.
Thank you I’m working on a unit now that I have to check all this because when I got there it was frozen so I told him I would be back the next day to hook up everything again and run it properly and see what’s going on before I condemn anything
As a tech, I love these videos.
some aircons have check (one way) valves that will give some of the same symptoms as a bad txv. if you are thourough in the diagnosis it will become obvious but always use both hi and lo gauges and check system temps in lots of places. its been rare to have a check valve fail but they can give you a real hard time if your not aware of them.
Brian so instead of running up and down from attic to condenser unit every time you warm or cool the TXV valve bulb what about taking advantage of the Fieldpiece or Testo probes along with the Measure Quick app and watch what you pressure's and temperatures are doing. Saves alot of running around for those that have them or frees up a second person. Also can probably use an infrared terminal immature on the TXV. Just a thought 🤔
I am never 100% sure when I condemn a Txv. It still feels like I'm guessing. One of my least favorite diagnoses.
Same. Some guys check pressures, SH, SC. Then, put txv bulb in hot water, and recheck those pressures,(suction should go up, feeding more refrigerant) you could also do ice water and txv should feed less and have lower suction. But others check pressures, SH,SC, but they even add refrigerant and see that suction deadends, again to Bryan's point, neither of these are practical. More so checking more things like discharge gas superheat off compressor. I've learned about having bad txv when changing a rusted drier, then added refrigerant charge to unit charging chart then the suction hit a deadend and wouldn't rise anymore upon adding refrigerant, the headpressure would also stack if much more refrigerant is added after that deadend. Not the best way to know, why I've been trying to find better approach.
Maximus Decimus Meridius lies, kink liquid line or clogged filter drier will increase head pressure along with liquid saturation temp which will show a subcool within range, or dirty condenser coil will raise liquid pressure and show subcool within range. Don’t feed false information to newbie techs bud.
Brian, thank you for your time and effort in making great content for us all to learn from. I work on commuter trains . We have 2 , 8 ton package units. In each unit There are 4 TXV's feeding 2 evaporator coils. There is liquid line valve and a branch circuit off the liquid line that incorporates a modulation valve, that when energized provides "Full cooling" capacity through feeding all 4 TXV's. Partial cooling capacity is accomplished by de-energizing the modulation valve and feeding only 2 TXV's . Question, Would I have to operate these units in full cooling to properly calculate SH? I've never seen a system with multiple TXV's like this before. There are no manifold gauge connections, only transducers and NTC thermistors mounted on the liquid and suction lines. We use R-407C refrigerant.
marty maness replace the txv and ll drier and you can’t go wrong.
i have a piston on my system, what's better Txv or piston. Should i be worried because i have a piston?
Thank you for this wonderful video.... I understand everything you explain in this video minus one factor. When you have a moment can you kindly explain why your DeltaT will go up when you have a bad TXV. Many thanks
If the TXV is underfeeding, there will be a noticable drop in pressure in the indoor coil. This will cause the coil to significantly drop in temperature. The air being pulled across will lose a lot more heat because of the colder than normal coil. This is what gives you a higher delta T.
It's always taping on the txv the diaphragm with a pen. Then have a new power head and listen to the sound. Push on the diaphragm. You will see the difference. Some alco or sporlan valves willo have a kit at RSD and you don't have to replace valve body. Just make sure it's the right power head. You can use a pressure limiting power head to shut down the system in case of refrigerant lost. Pumping down and pulling a vacuum will allow you to do this.
The video is very informative for technicians who knows all this stuff already.
For me who just starting to learn about hvac is a headache listening 10 words in a second .
Cutting the video clips to make a shorter video doesn't help me.
Have you tried playing it at .5 or even .25 speed?
Bryan great video as always, but ive always wondered and asked what refrigerant is used inside of a sensing bulb. It would make sense to me that the bulb would have a small amount of liquid refrigerant of whatever the system uses that its rated for but i have never been able to find documentation or get a definitive answer. Just a question ive had for 10 plus years.
Carrier tech support helped me diagnose the txv. Seems like your saying high superheat, low suction pressure, good subcooling is what we are looking for.
I pretty sure this is a class for HVACR technicians Continue Education, but not a class for newbies like me. Will come back after I have certain HVAC knowledge
Check out their TH-cam home page and look under the 'refrigeration basics' category - lots of great stuff for newbies!
Visit back often. Once you get more experience you can picture what Brian’s talking about 😄
our teacher who had at the time little over 35 years in the trade told us that 3 degrees in HVAC is close enough and dont sweat it too too much ,,,,just cool that house LOL ,,,,specially in miami /ftlaud / etc southern fl,,,nice show
Thanks Bryan great video technician going possible back into field after 14 years in house maintenance. Probably watch again.Beer can cold days are long over. Thanks got your app on my phone!
flawless articulation of details
you are the best master in my country. Republic of Kosova. Thanks for all.😇
Best tool for manipulating a TXV bulb is a ‘hot hands’ warmer. You don’t have to disturb the factory insulated connection.
that was a lot of information in a short amount of time.....but well done!
Great job sir , from Trinidad and tobago.
Deon's air conditioning services here
I bought a brand new home. 9 months into it, the builder, who is preparing to replace my laminate flooring, takes a picture of my dry mulch and tells me my a/c is broken! I knew my a/c wasn't broken, it was set on 73 and it was 69 in the house, (cold outside and it's been running perfectly, so I told the builder if he thought my a/c was broken, then he'd better call the a/c man. Well, the man came out, didn't speak to me, took both of my units apart, took the txv out, welded, worked on both units for a total of 3 hours jeri-rigged the a/c so it would run at 60 degrees. The 9th day, he came back, spent another 3 hours welding and taking things apart, said he gave me a new txv, and left. No paperwork. I asked him why. He said the txv would have gone out down the road. What? He fixed it before it was broke? Before anything was broke? What was that about??
Thanks for the video!
22 year old Trane R22 system. XE1200 with a TXV on coil. (13 Seer) Condenser coil very clean. Evap coil can't be observed, without cutting case. (Probably dirty, after 22 years.) Outdoor temp 90 degrees. Super Heat is 49. Sub Cooling is 17. (Coil paperwork calls for 16 nominal sub cooling.) Liquid line / head is 210 psi and suction line is 49 psi. Obviously freezes up and looses ability to cool below 74'. Trane factory dryer / filter on condenser does not reflect difference in temps across. Liquid pressure line temp outdoor is 85' indoor is 82'. 25' delta T. Sounds like TXV to me. I will test the TXV bulb by dipping in cooll to hot water and watch the low pressure this week. Feedback welcome!
That was an excellent presentation.
I feel really smart TH-cam is recommending this to me and I have no idea what the hell this guy is talking about. But everything that breaks gets fixed in my house so I guess one day this video will come in handy!
In easy words, restriction means: a mass flow of refrigerant is flowing inside the pipes very little although you have enough refrigerant level in the system.
Great lecture for TXV
Slow down, don't worry about low temp Refrigeration. Stay focused and get to the point
I actually like the speed of his explanation.
one time I suspected a kink and the line temp difference between ID and OD was like 15-20 degrees. I searched and sure enough the lineset was bent where it exited the wall cavity.
So was the indoor temperature of the suction line more normal and the temperature of the outdoor line really low?
Every TXV I have had a problem with was gummed up. Just take it apart and clean it with a brass wire brush and nonclorinated brake parts cleaner. Reassemble evac and dump the charge back in. I replace the filter dryer too when I opened the lineset.
Very interesting class it really helped me a lot on my Jobs thank you God bless you brother
Awesome video 👍. Such a valuable information.
You can also cover the condensing fan or unplug it and watch the head pressure go up and your suction pressure should maintain and not move at all this is a good txv if your suction and liquid line increase bad TXV
Thank you very much for the wonderful explanation. Rony - from Israel
Great information.. well explained thank you👍👍👍👍👍👍
on a traulsen two door commercial refrigerator can the body of the txv sit externally? outside the evaporator housing? as long and the bulb is inside?
I actually check the bulb when I suspect underfeeding. I'm weird. I carry sandpaper in my back-pocket. Why? because it don't hurt. Worst case you wind up with a cleaner copper tube. But even though air-flow is a pretty large and intimidating area of HVAC, you know what isn't? Checking for dirty filters or iced/gunky coils. Takes almost no effort. Video was very informative. I'm a new tech., I try my best to stick to basics....but we tend to panic and check backwards. I have no idea why I do that when i panic. I'll look for the most convoluted problems, but it's rare. It's usually beyond simple.
Like bad drain lines, dirty, a loose connections, ect...
I find with most airflow issues the sc will be ok and the suction pressure will be low and the sh will be really low too because thier isn’t enough heat to boil the refrigerant in the evap coil. Not always buy most times that is the case
Excellent training!!
Very nicely explained Bryan. Thanks
Your explanation is perfectly correct and clear about txv valve sir im electro. Mechanical sir how about step motor sir
That does make sense that superheat would be high. I must admit I’m the guy who grabs my tank. If it starts running right, I look for the leak. If the head pressure starts to sky rocket, I’m over charged and have a bad txv. And it seems like a a couple ounces makes a big difference.
Common issue with installers over heating the suction line on units while brazing and burning up the temperature bulb and causing the txv to remain closed. Causing compressor to pull a suction side vacuum.
if you had a wet rag wrapped around the bulb it should be fine.
I’ve been installing high efficiency equipment for 25 years, purging with nitrogen and keeping TXV’s cool while brazing. I’ve had plenty of failures between 4-8 years. Chinese sourced, poor US engineering.
@@p.imprint your right or thermal paste and simple remove the bulb. Its a lack of training in proper technics from my experience.
Using a clamp on superheat will tell you if that valve is bad or bulb unattached. There should be a 5 psi pressure drop across the valve.
Absolutely great explanation thank you for that
Good talk. It did exploded my head.
Love the information on all aspects of an air conditioning system. My question is on the TXV bulb does the pig tail " this is what I call it " on a vertical line need to be in the up position and insulated? Thanks for the feedback.
Yes, they're charged with refrigerant, install the small line coming off the bulb up when it's in a vertical position. Horizontal is preferred, just keep the bulb from the bottom of the line. Somewhere between 9 and 3 o'clock.
@@charlesb7418 thank you very much for the feedback.
Speaking so fast it's not enough time to allow for proper understanding of your point.
Slow down a bit and allow time to connect the points you're bringing out!
@@MrExtremec4 you can change the playback speed to get it slower.
Got some real issue with a chilled water bank system. It's a R22gass system, using ×2 Copland (6.8) hp rottary compressors and 2 TGEX expansion valves the system is a water cooled condenser. Issue here is am getting a very high head pressure even causing the relief valve to engage at 300psi (which it's labled) even besides dropping the gas level to a point were the LP switc (electronic) regards low in sync with my guages low side when I push on the contactor the head pressure doesn't seem to stop rising NOTE this is a brand new system has never worked since purchase date what would be the issue
Explain very well, I learned a lot 👍
Priceless information 👌
Professional and precise and very detailed
Great job and video like always
Great video like always 🙏🏻
Very helpful information thank you
That was outstanding instruction. Well done.
thanks!
Great video. Add a hot gas bypass system with liquid quenching to this and troubleshooting gets even more interesting. Then throw in flooded condenser and it's a party.
VERY good explanation keep up the good work
I always questioned the reasoning behind "clocking the bulb" so it doesn't sense the liquid. Umm, it's at the outlet of the evaporator on a copper tube. Right?