Pull condensing fan wire to stop fan and see if your suction pressure maintains the same pressure the head pressure will start to climb but suction pressure will stay the same this would mean the TXV is working to maintain conditions in evaporator coil
Just installed a brand new system last week. It had high suction pressure with low super heat and sub cool on startup. Didn't want to deal with it but had too, was a bad txv on startup. Replaced TXV, system now checks OK. Went home satisfied!
Sounds like a lennox..the factory at the moment is releasing txv screens with copper shavings inside the socket..which the only way it can get in there is a txv with overbored valve and when it gets in use it starts shaving the excessive bore out of the txv it self
@@gar351 trane indoor txv tends to leak on the bottom nut that they install.too i went on a call one time and found the bottom nut of the txv loose causing a slow 6 month leak to dry
You have low sub cooling and low superheat (flooded evaporator), that equals a txv that is over feeding. Check txv make sure bulb is making good contact and insulated. Place bulb in ice water and that should close the valve. What was the OA temp, that should guide what head pressure should be.
When I had my A/C system installed 20+ years ago, I had the option of going with a TXV or piston in the system. After talking to a senior HVAC tech at work, he said you will gain some performance using a TXV, but you will have better reliability with a piston since the TXV has moving parts and are known to fail. I went with the piston and I'm glad I did.
@@virtual_bomber5698 I see your point on that, but in my experience with residential i have only ever had one issue with a piston and that was a new install and it was put in backwards by the installers. Made the head pressure go crazy, like 140 psi then 300 psi and back and forth. that was a new one for me. Of course, the customer was not home and i had no access to the indoor unit that was in the attic. I Replaced at least 2 txvs every year i worked. On the commercial side i have come across a few restricted orifices in package units. Not very often but it happened enough for me not to want the carrier units with them in it.
How can you know you are glad, could have had the same reliability from the TXV. using your logic you should forgo a thermostat, because they can fail. You can assume to duties by using a simple switch to cut the system on when you are hot, and cutting it off when you are cold.
great troubleshooting process… i’m an IT guy so i dont know HVAC other than being a armchair quarterback but i really like how you do your troubleshooting and dont just assume its one thing or another. all that being said, i do agree that the TXV is not properly regulating the amount of refrigerant.
Either weak compressor or txv overfeeding. The txv overfeeding makes me think you'd have higher head pressure, though, due to the added BTUs from the increased refrigerant flow. I guess there's a point where you get diminishing returns on feeding more refrigerant. At some point the feed rate is higher than the compressor can move to maintain enough of a compression ratio. I'd close the high side down and see how fast the compressor pumps down. I'd also mess with the service valve a bit, closing it partially to force a bit higher head pressure. If it pumps down at a decent pace and if partially closing the high side service valve makes the condenser start blowing heat, then I'd feel more comfortable calling the txv.
That's a very interesting way to check your txv, can you explain how closing the service valve would help you diagnose the txv please? The only dumb question is the one that's unasked
@@kevinkrug466 think of it this way. If the TXV is overfeeding, then choking down the service valve will provide some resistance, so the condenser can get some subcooling and a higher head pressure. This would result in the condenser heating up and you'd feel it rejecting heat. If the compressor is weak, you won't get higher head pressure and the resulting heat. You wouldn't be able to measure the condenser head pressure during this test since the port is after the service valve, but you'd know it had a higher head pressure because of the added heat blowing out of the condenser. You could also monitor the running amps during the test to verify the compressor is building pressure.
@@gquin9487 I would only focus on the condenser. Closing down the service valve would essentially distribute the evaporator area up to the service valve, so the results on the low side would be inconclusive.
I didn't pay attention from the start on this one. I didn't realize it was a heat pump (I was thinking straight cool with electric heat). If there's a check valve somewhere, it might be internally leaking. Maybe even the transfer valve (I'm spacing the name) could be bypassing. This would add another variable. I really am hesitant to call the TXV on this one. It's behaving opposite from how TXVs typically fail (underfeeding).
Would love to see the repair and final conclusion once repaired. I agree it’s likely the txv. Possibly weak compressor. Thanks for sharing looking forward to a follow up video
Love your channel. On this call, you called out what pressures you were getting. I appreciate that because we can't always tell from the screen what is on your cell phone app....the numbers are small and often blurry and you don't let the camera stay on the app for long. We do HVAC and MVAC here and we try to diagnose along with you
@@onenikkione You have to here in Texas. We have clay soil. We have sprinkler systems to water the grass and another drip irrigation system by the foundation.
I think you nailed it but I want to see the pump pump down rate and if a question still linger, recover the refrigerant with a scale to check the charge and saturation pressure to confirm that R 410a with correct charge. Then evaluate.
I went with my boss one day and found a carrier with this exact same problem, we deduced that due to the extra amp and a half pulll on the compressor windings we seemed to think flooding back and wide open TXV,, sure enough that fixed the problem
Yeah I'm in agreement with the others that mentioned the sensing bulb. Obviously it needs to be insulated and firmly attached to one of the upper quadrants of the suction line. I couldn't see it in the video and didn't see a bulge in the insulation on the suction line. Good luck, and looking forward to the follow up.
I recently had the same issue, and as others have said, removing that bulb, placing it on the exterior, and watching just helped me. Good stuff here...
I know in Georgia you have high latent heat loads , that may account for some of your delta tee. There is a formula where by you measure the time it takes to produce 1 pint of condensate, do some simple math and it will tell you exactly how much tonnage you're re moving in latent heat. I'm sorry I can't come up with it now, but I'll work on it.
I think it is the txv. Like others have said down below, only way to know for sure if the txv is working is to remove the bulb and let it hang outside the unit or heat it up and see if anything changes. Unless the compressor had really low amp draw and was leaking by then i am pretty sure it is the txv.
Hey brother I had one today I think you will get a laugh out of........The man that works on my auto's ....his daughter is his secretary.....she call's me and ask if I would go look at her daughter's ac........when I get there the husband who looks like he might be in his early 20's is waiting in the yard......So I pull up next to the unit....it's a Payne gas pack......I get out and ask the young man what the unit is doing......he says.....lolrofl.....it stopped working yesterday.....so I watched some video's on RUclips and thought it might be the capacitor so I took the panel off and looked at it and when I went to put the screws back in the door panel it cuts off.....lol.....he said but if I just leave out the one screw on the panel it stays running......lolrofl.......First thing I did was grab my meter .......lol......cause I know there's a short in this unit somewhere lol.......and I didn't want to get my false teeth knocked out......I checked it from the unit to the gas line.......What I found was one of the wires from the high pressure switch had arced against the cap tube of the txv bulb ........I put some tape on it and hung it where it wouldn't rub anymore and closed up the unit...lol.... before I left I told him not to watch any more videos and try to work on this unit anymore .....I told him there are things in here that will kill you.....lolrofl
I want to believe it is a faulty, maladjusted or incorrect TXV. An inefficient compressor would typically cause high superheat due to the compressor not pumping and starving the evaporator. Taking amp draws possibly could've ruled that out or not. I'm curious to see what it was, it has me guessing.
Yes plenty of info .......the only thing I would have done different is I would have removed the bulb to see what happened if I stuck it outside the cabinet and I would have cleaned it and the suction line before reinstalling to see what that did
Not sure I would advise warming the bulb. Considering how little superheat you presently have here, and if TXV is only stuck partially open, you are guaranteeing a flood back if the TXV decides to fully open. That could potentially damage the compressor.
You mean 10 degree delta t. Disconnect the condenser fan motor when its running and see what your pressures are doing. run toy head pressure up and your low Sid pressures should remain the same to a point.
When the TXV went out on my carrier I thought, not knowing any better, that a leak had developed over the winter. The compressor sounded like it had no refrigerant all the while making that distinctive gurgling noise. I thought I was headed for a A-coil replacement but turned out the TXV was totally closed and would no longer operate.
TXV's always get me second guessing. Great video 👌. I sometimes get a warm cup of water and put the bulb in it to see if it changes anything. But that only works 90% of the time, half the time lol
A B C Air before charge Always start with static pressure and fan speed using your manometers,after you have verified correct CFM per Ton, refrigerant levels can then be checked.
If it is a txv system, then how do you start to troubleshoot this with an obvious low SC compared to mfr specs, usually 11° or so on Carrier equipment. Also, the txv is set to maintain 15° SH. Verify air flow, that's number one. The motor isn't going to be too different with the door off when you change speeds and will be lower RPMs with the door off vs on. Next, pull the txv bulb and hold it in your hand to warm it up. You should be able to see the change in pressures. No change, bad txv. If it does change, I would probably add some refrigerant to see what SC does. Based on what happens will point me down the path to my next step.
How did the system perform in the heating mode?? I guess any reversing valve issue; like hot gas bypass into the suction line would raise the low side pressure but the super heat would go up??
The TXV used to be almost full proof. Nowadays they are built like junk. The only thing I would have done is taken the bulb in my hand or warm water and see if that would make any changes. All in all - I would have condemned the TXV too. Good call !!
Curtis that is a fun one. The low super heat and higher low pressure gives it away. Just bad txv. Is that a heat pump? Can you switch it over and see if the outdoor txv works? I liked that video. Thanks
ICON said:" [I] would have just pumped it down, and got me a piston out, put it in, vacuum, takes 30 minutes on those bolt in deals.." Don't know where you live but I live in Louisiana and down here, we never go into our attics until January. Curtis lives in one of the Carolinas which makes going into the attic a medical emergency. 🥵
You are a very good troubleshooter I think! you can get the job done and move to the next. I have a question though? What brand and model is that little bity small thermal camera you used to see if breakers were getting hot in another video?
I dont know if HVAC GUY responds to comments. Hopefully he has thoughts on the new 454B and R32 freon that should be out next year. I think they are flammable unlike 410.
I’ve seen this problem before and it turned out the high suction was due to a check valve leaking by. If the check valve on this one is in the txv then it’s a txv problem. Looks like it’s over feeding when in reality the refrigerant is expanding at higher pressure and losing capacity.
@R P When a txv over feeds you won’t have such a low temperature split between Return and supply. Gotta look at air side temperatures too. A call like that is really a head scratcher. I would’ve liked to see that bulb in submerged in cold ice to really rule out the overfeeding possibly. Again everyone thinks differently. The other day I was working on a 15 ton carrier system. My pressures were 300/148 my temperature split was only 6 degrees. System has two compressors working in tandem on one refrigeration circuit It turned out one txv was completely shut and the other txv was working fine.
@R P two things would’ve done to diagnose a txv if I think it’s over feeding. First is to close the high side to and monitor my suction line and the performance of the compressor. Second is to dip that bulb in ice and watch what happens.
So if the txv is not metering right, then there’s too much refrigerant on the evaporator. Ok . But I am having hard time understanding how to fit the 10 deg DT
Hi HVAC Guy. Im Joaquin Miranda and I want to know what do you mean when you say “it is starting to flood back…” Another thing, what happens if I put more refrigerant and nothing happened, like subcooling and superheat do not go up?
Could a bad outdoor txv cause trane heat pump to pump down in both heating and cooling? I am so stumped and you seem like you may have run into that problem before based on your experience level
It reminds me of one I had many years ago that was going off on thermal overload, and it was because it was overfeeding. And the system wasn't very old it was only a couple years old and still under warranty. I replaced the evaporator coil because it came with the TXV on it. go to start it up the compressor wouldn't run, I put a compressor in it. start it up it ran just like I did before, overfeeding and the only thing I could figure was the ducts, but why was it overfeeding. And with its overfeeding the compressor would eventually go off on thermal overload. the only thing I could do to keep it running and to cool a little better, was to drop a bunch of charge out so the evaporator wasn't flooded. The pressures made no sense but it would work and stay working. So it had a new evaporator and compressor and it still worked the same way as it did when I got there. What a nightmare that was. I didn't want to do any more on it. I'm pretty sure I calculated the CFM and replaced all the freon in case it was contaminated, but nope it wouldn't stop over feeding. I got it to work a little better and I got going.
Moving the temp clamps back and forth isn't always going to give you an accurate reading. I use a wire brush to clean the pipe if I have a abnormal readings before final diagnosis
Probably is the TEV. If it were restricted a little more you’d also see that suction pressure drop’to a more reasonable level. Can you not trynadjusting the superheat on the TEV body?
Why are HVAC service tech notorious for leaving old parts & pieces laying around after they’ve worked on a unit????? Just a pet peeve of mine after being in the HVAC business for over 50 years!!!!!
Was the sensing bulb mounted inside the cabinet ?. You would want it outside of the cabinet so you read proper Subcooling. That’s insulated of course. If it’s left inside the cabinet uninsulated your reading box temp.
Those pressures were almost identical to the one I just left it was a trane dual pack. I installed a evaporator coil and I know I didn't get my txv to hot because I had it covered in heat block putty and a cold wet rag. Had a bad txv on startup just stuck open. Worst part is its for a guy on his death bed new txv won't be here till Wednesday. I offered to put a danfoss but advised it would void his warranty if he ever used another company and they wanted to throw a fuss. He decided to wait till Wednesday
5kw is usually what sticks on, it negates 17000w or 1.5 ton of cooling. So, if you have a 3 ton, a TD of 10F would be expected. I still think compressor or txv. Either way, new drier 410A. You may have non-condensibles in the system too. No low balling.
My two cents.. Low on refrigerant charge.. 1 sub-cool low... 2 Liquid pressures on the high side is Low of the outdoor temperature is above 86 to 90 degree F and the condenser coil is clean. 3 you need liquid refrigerant pressure on the TXV to force it open aswell as to produce the flash gas to expand in the evaporator for your sensing bulb to respond by closing the TXV to control the super heat... Add some refrigerant to bring up the sub-cool and let it run for some time and watch the suction pressure drop and your super heat rise.. Some feed back would be nice if possible.
Because I don’t know if anyone work on it just before me and what did they do it I tell the customer this is what I need to do to start with Or you think it is batter to start by changing parts TXV, then a compressor, ……….. either way repaire is going to be expensive
I had this thought too. You could pump down into a recovery cylinder and measure the pressure and temperature to verify the integrity of the existing refrigerant.
@@denrayr that would be a more reasonable approach. With the price of refrigerant these days, telling a customer to replace refrigerant on a gamble is rough.
That is a good point at least checking the refrigerant Dennis I agree we live in defiant times all you can do is give customer appreciations same Companies give you one option you need a new system collect the service fee and move on Maybe it’s time to call blueon for support😊
Cuties You can use analog gauges and while it’s running disconnect the common wire on the condenser fan. As the head Head pressure increases the The suction gauge should remain steady. I saw this on the mentors RUclips channel.
Most txv fail closed. I’ve never seen a txv fail open. You have 2 closing forces internally to a txv with only 1 opening force (the bulb). So when the bulb loses its charge or doesn’t touch the pipe the valve loses its ability to open. Your pressures and temperatures indicate the valve open and unrestricted. It’s open because there is not enough liquid refrigerant to cool the suction line enough to force it closed. Clean your condenser coil and add some refrigerant. If you’re not comfortable adding refrigerant, recover what is in the system currently while weighing it as it comes out to verify your charge is correct.
Yank the sorry damn TXV out and put a piston in it.. Done and ya (NEVER) have to worry about it happening again, in fact with that being carrier, i would have just pumped it down, and got me a piston out, put it in, vacuum, takes 30 minutes on those bolt in deals.. A txv to piston isn't gonna change the seer rating much at all... Only difference is one meters flow off temperature and the other by orfice size. That's it the end! If it's not a EEV, then it's not worth the time or trouble of installing! TXV's are the (WORST IDEAL) they ever came up with!! Hell i bet i change 20 per year at (LEAST)!! Hell i have seen them go bad on systems less than 2yr old in fact!!
For these txv's you need to have around 10° subcooling for them to meter properly. Make sure the sensing bulb is correctly placed, I would aim closely around the 7 or 5' O'clock position. And make sure the bulb is tightly wrapped. I use monkey shit. How this helps.
Your slugging back cause the liquid is flashing off, pushing the liquid. I have found that if your not over 3.7° SC you will have liquid flashing at AH.
Pull condensing fan wire to stop fan and see if your suction pressure maintains the same pressure the head pressure will start to climb but suction pressure will stay the same this would mean the TXV is working to maintain conditions in evaporator coil
Do you mean i disconnect condenser fan motor?
Just installed a brand new system last week. It had high suction pressure with low super heat and sub cool on startup. Didn't want to deal with it but had too, was a bad txv on startup. Replaced TXV, system now checks OK. Went home satisfied!
Thanks for sharing!!
That's why pistons are way better. They don't go break.
Sounds like a lennox..the factory at the moment is releasing txv screens with copper shavings inside the socket..which the only way it can get in there is a txv with overbored valve and when it gets in use it starts shaving the excessive bore out of the txv it self
@@DJV94022 I would agree with everything you said about Lennox, it was a Trane however. It was stopped lol! New txv fixed the issue.
@@gar351 trane indoor txv tends to leak on the bottom nut that they install.too i went on a call one time and found the bottom nut of the txv loose causing a slow 6 month leak to dry
You have low sub cooling and low superheat (flooded evaporator), that equals a txv that is over feeding. Check txv make sure bulb is making good contact and insulated. Place bulb in ice water and that should close the valve. What was the OA temp, that should guide what head pressure should be.
Best comment here
This is what I was thinking
You shouldn't have ignored that call that came in. They probably wanted to inform you of your vehicles warranty expiring! LOL! Great video!
When I had my A/C system installed 20+ years ago, I had the option of going with a TXV or piston in the system. After talking to a senior HVAC tech at work, he said you will gain some performance using a TXV, but you will have better reliability with a piston since the TXV has moving parts and are known to fail. I went with the piston and I'm glad I did.
Personally, I don’t agree with that one.
Again, personally, I’ve come across more restricted orifices than bad TXVs.
@@virtual_bomber5698 good to know
@@virtual_bomber5698 I see your point on that, but in my experience with residential i have only ever had one issue with a piston and that was a new install and it was put in backwards by the installers. Made the head pressure go crazy, like 140 psi then 300 psi and back and forth. that was a new one for me. Of course, the customer was not home and i had no access to the indoor unit that was in the attic.
I Replaced at least 2 txvs every year i worked. On the commercial side i have come across a few restricted orifices in package units. Not very often but it happened enough for me not to want the carrier units with them in it.
How can you know you are glad, could have had the same reliability from the TXV. using your logic you should forgo a thermostat, because they can fail. You can assume to duties by using a simple switch to cut the system on when you are hot, and cutting it off when you are cold.
Txv is like going rotary piston well its a piston engine
great troubleshooting process… i’m an IT guy so i dont know HVAC other than being a armchair quarterback but i really like how you do your troubleshooting and dont just assume its one thing or another. all that being said, i do agree that the TXV is not properly regulating the amount of refrigerant.
Either weak compressor or txv overfeeding. The txv overfeeding makes me think you'd have higher head pressure, though, due to the added BTUs from the increased refrigerant flow. I guess there's a point where you get diminishing returns on feeding more refrigerant. At some point the feed rate is higher than the compressor can move to maintain enough of a compression ratio. I'd close the high side down and see how fast the compressor pumps down. I'd also mess with the service valve a bit, closing it partially to force a bit higher head pressure. If it pumps down at a decent pace and if partially closing the high side service valve makes the condenser start blowing heat, then I'd feel more comfortable calling the txv.
That's a very interesting way to check your txv, can you explain how closing the service valve would help you diagnose the txv please? The only dumb question is the one that's unasked
@@kevinkrug466 think of it this way. If the TXV is overfeeding, then choking down the service valve will provide some resistance, so the condenser can get some subcooling and a higher head pressure. This would result in the condenser heating up and you'd feel it rejecting heat. If the compressor is weak, you won't get higher head pressure and the resulting heat. You wouldn't be able to measure the condenser head pressure during this test since the port is after the service valve, but you'd know it had a higher head pressure because of the added heat blowing out of the condenser. You could also monitor the running amps during the test to verify the compressor is building pressure.
@@denrayr that's a great way of explaining that, thank you for responding
@@gquin9487 I would only focus on the condenser. Closing down the service valve would essentially distribute the evaporator area up to the service valve, so the results on the low side would be inconclusive.
I didn't pay attention from the start on this one. I didn't realize it was a heat pump (I was thinking straight cool with electric heat). If there's a check valve somewhere, it might be internally leaking. Maybe even the transfer valve (I'm spacing the name) could be bypassing. This would add another variable. I really am hesitant to call the TXV on this one. It's behaving opposite from how TXVs typically fail (underfeeding).
Would love to see the repair and final conclusion once repaired. I agree it’s likely the txv. Possibly weak compressor. Thanks for sharing looking forward to a follow up video
Love your channel. On this call, you called out what pressures you were getting. I appreciate that because we can't always tell from the screen what is on your cell phone app....the numbers are small and often blurry and you don't let the camera stay on the app for long. We do HVAC and MVAC here and we try to diagnose along with you
We had a cold front the other day here in North Texas. The high only reached 99. Thank goodness for some relief!
Sounds like we have similar temps. Only we get regular afternoon showers. It’s humid, but it does provide some relief
RELIEF!!! Relief is spell R-O-L-A-I-D-S
@@HVACGUY I wish we had afternoon showers. I have to water my home foundation almost daily due to the lack of rain.
@@TM_Stone never heard of having to water a home foundation 🤔
@@onenikkione You have to here in Texas. We have clay soil. We have sprinkler systems to water the grass and another drip irrigation system by the foundation.
I do agree 100% that it's the TXV. I'm wondering if the sensing bulb may have come loose?
I think you nailed it but I want to see the pump pump down rate and if a question still linger, recover the refrigerant with a scale to check the charge and saturation pressure to confirm that R 410a with correct charge. Then evaluate.
I went with my boss one day and found a carrier with this exact same problem, we deduced that due to the extra amp and a half pulll on the compressor windings we seemed to think flooding back and wide open TXV,, sure enough that fixed the problem
Yeah I'm in agreement with the others that mentioned the sensing bulb. Obviously it needs to be insulated and firmly attached to one of the upper quadrants of the suction line. I couldn't see it in the video and didn't see a bulge in the insulation on the suction line. Good luck, and looking forward to the follow up.
Looking forward to the follow up on this one
I recently had the same issue, and as others have said, removing that bulb, placing it on the exterior, and watching just helped me. Good stuff here...
I know in Georgia you have high latent heat loads , that may account for some of your delta tee. There is a formula where by you measure the time it takes to produce 1 pint of condensate, do some simple math and it will tell you exactly how much tonnage you're re moving in latent heat. I'm sorry I can't come up with it now, but I'll work on it.
You said you going to check the filter too. It look like there was some dust on the outside on the ceiling.😀
I think it is the txv. Like others have said down below, only way to know for sure if the txv is working is to remove the bulb and let it hang outside the unit or heat it up and see if anything changes. Unless the compressor had really low amp draw and was leaking by then i am pretty sure it is the txv.
Lotta people on here trying to tell you how to do your job. Thanks for the video!
Yep I concur ... Good call ... Thx for posting ...
Curtis u are a great man ur customers love u ❤️ I know they do u do outstanding 😊😊
Hey brother I had one today I think you will get a laugh out of........The man that works on my auto's ....his daughter is his secretary.....she call's me and ask if I would go look at her daughter's ac........when I get there the husband who looks like he might be in his early 20's is waiting in the yard......So I pull up next to the unit....it's a Payne gas pack......I get out and ask the young man what the unit is doing......he says.....lolrofl.....it stopped working yesterday.....so I watched some video's on RUclips and thought it might be the capacitor so I took the panel off and looked at it and when I went to put the screws back in the door panel it cuts off.....lol.....he said but if I just leave out the one screw on the panel it stays running......lolrofl.......First thing I did was grab my meter .......lol......cause I know there's a short in this unit somewhere lol.......and I didn't want to get my false teeth knocked out......I checked it from the unit to the gas line.......What I found was one of the wires from the high pressure switch had arced against the cap tube of the txv bulb ........I put some tape on it and hung it where it wouldn't rub anymore and closed up the unit...lol....
before I left I told him not to watch any more videos and try to work on this unit anymore .....I told him there are things in here that will kill you.....lolrofl
I want to believe it is a faulty, maladjusted or incorrect TXV. An inefficient compressor would typically cause high superheat due to the compressor not pumping and starving the evaporator. Taking amp draws possibly could've ruled that out or not. I'm curious to see what it was, it has me guessing.
Yes plenty of info .......the only thing I would have done different is I would have removed the bulb to see what happened if I stuck it outside the cabinet and I would have cleaned it and the suction line before reinstalling to see what that did
This is exactly what I do to check a txv.
Not sure I would advise warming the bulb. Considering how little superheat you presently have here, and if TXV is only stuck partially open, you are guaranteeing a flood back if the TXV decides to fully open. That could potentially damage the compressor.
You mean 10 degree delta t. Disconnect the condenser fan motor when its running and see what your pressures are doing. run toy head pressure up and your low Sid pressures should remain the same to a point.
When the TXV went out on my carrier I thought, not knowing any better, that a leak had developed over the winter. The compressor sounded like it had no refrigerant all the while making that distinctive gurgling noise. I thought I was headed for a A-coil replacement but turned out the TXV was totally closed and would no longer operate.
According to "Wayne's Brain™ Air Conditioner Analyzer" TXV overfeeding (compressor damage possible)
TXV's always get me second guessing. Great video 👌. I sometimes get a warm cup of water and put the bulb in it to see if it changes anything. But that only works 90% of the time, half the time lol
A cup of ice water would work as well, dip the bulb in to see if superheat goes up , if superheat stays the same , bad valve
A B C
Air before charge
Always start with static pressure and fan speed using your manometers,after you have verified correct CFM per Ton, refrigerant levels can then be checked.
I think it is the txv and I would make the same call and tell me if I am wrong!! Like to always learn and how to become better at my job.I'm
yep that TXY well it may have a plugged screen so it needs to go. if you change it look for the screen or a chunk of something in the nedel.
It would have been nice to see how the suction pressure and superheat responded to the coil door being off.
If it is a txv system, then how do you start to troubleshoot this with an obvious low SC compared to mfr specs, usually 11° or so on Carrier equipment.
Also, the txv is set to maintain 15° SH.
Verify air flow, that's number one. The motor isn't going to be too different with the door off when you change speeds and will be lower RPMs with the door off vs on.
Next, pull the txv bulb and hold it in your hand to warm it up. You should be able to see the change in pressures. No change, bad txv.
If it does change, I would probably add some refrigerant to see what SC does. Based on what happens will point me down the path to my next step.
How did the system perform in the heating mode?? I guess any reversing valve issue; like hot gas bypass into the suction line would raise the low side pressure but the super heat would go up??
The TXV used to be almost full proof. Nowadays they are built like junk. The only thing I would have done is taken the bulb in my hand or warm water and see if that would make any changes. All in all - I would have condemned the TXV too. Good call !!
Curtis that is a fun one. The low super heat and higher low pressure gives it away. Just bad txv. Is that a heat pump? Can you switch it over and see if the outdoor txv works? I liked that video. Thanks
ICON said:" [I] would have just pumped it down, and got me a piston out, put it in, vacuum, takes 30 minutes on those bolt in deals.." Don't know where you live but I live in Louisiana and down here, we never go into our attics until January. Curtis lives in one of the Carolinas which makes going into the attic a medical emergency. 🥵
You are a very good troubleshooter I think! you can get the job done and move to the next. I have a question though? What brand and model is that little bity small thermal camera you used to see if breakers were getting hot in another video?
The little thermal camera is made by Klein.
I dont know if HVAC GUY responds to comments. Hopefully he has thoughts on the new 454B and R32 freon that should be out next year. I think they are flammable unlike 410.
when will 410a start being phased out?
Like the bag I got the mct camo love the bag did it when the promo was going on so I got a free bag for getting that one
Can relocating the sensing bulb possibly fix that problem?
Most of the videos I’ve watch of yours, your mostly in the shade .. ain’t that lucky
I'm so sad to see you have a new bag.
Go for it.
Ha! Heard your phone buzzing and thought it was mine!
Just curious is the evaporator- air handler sized properly to match outside unit?
I’ve seen this problem before and it turned out the high suction was due to a check valve leaking by. If the check valve on this one is in the txv then it’s a txv problem. Looks like it’s over feeding when in reality the refrigerant is expanding at higher pressure and losing capacity.
@R P
When a txv over feeds you won’t have such a low temperature split between Return and supply. Gotta look at air side temperatures too. A call like that is really a head scratcher. I would’ve liked to see that bulb in submerged in cold ice to really rule out the overfeeding possibly. Again everyone thinks differently. The other day I was working on a 15 ton carrier system. My pressures were 300/148 my temperature split was only 6 degrees. System has two compressors working in tandem on one refrigeration circuit It turned out one txv was completely shut and the other txv was working fine.
@R P lol definitely and leave it like that so next time I go there it’ll be a txv and two compressors to replace. Great for the business
@R P two things would’ve done to diagnose a txv if I think it’s over feeding. First is to close the high side to and monitor my suction line and the performance of the compressor. Second is to dip that bulb in ice and watch what happens.
@R P sure I waste lots of time but bring the high dollars at the end of my day 🤫
So if the txv is not metering right, then there’s too much refrigerant on the evaporator. Ok . But I am having hard time understanding how to fit the 10 deg DT
Well I’m in Indianapolis but I didn’t call you. Lol 😂
Hi HVAC Guy. Im Joaquin Miranda and I want to know what do you mean when you say “it is starting to flood back…”
Another thing, what happens if I put more refrigerant and nothing happened, like subcooling and superheat do not go up?
Could a bad outdoor txv cause trane heat pump to pump down in both heating and cooling? I am so stumped and you seem like you may have run into that problem before based on your experience level
Veto pro bags are the best
It reminds me of one I had many years ago that was going off on thermal overload, and it was because it was overfeeding. And the system wasn't very old it was only a couple years old and still under warranty. I replaced the evaporator coil because it came with the TXV on it. go to start it up the compressor wouldn't run, I put a compressor in it. start it up it ran just like I did before, overfeeding and the only thing I could figure was the ducts, but why was it overfeeding. And with its overfeeding the compressor would eventually go off on thermal overload. the only thing I could do to keep it running and to cool a little better, was to drop a bunch of charge out so the evaporator wasn't flooded. The pressures made no sense but it would work and stay working.
So it had a new evaporator and compressor and it still worked the same way as it did when I got there. What a nightmare that was. I didn't want to do any more on it. I'm pretty sure I calculated the CFM and replaced all the freon in case it was contaminated, but nope it wouldn't stop over feeding. I got it to work a little better and I got going.
Had same issue today on a GOODMAN.. TXV was overfeeding
What ever happen with this call, was it the txv? Thanks.
Is there a test with or without air filter? 3:31 couldn`t tell if dirty
I’m sure you’ve answered this before but what tablet holder do you have? Thank you!
I was wondering if he was sucking attic air into the return
I have the same problem with that app. I don’t like having to log in every time I use it.
It's pretty useless with no internet service.
Change the txv and your good 👍
Fieldpiece needs to address how slow that app loads. Also how it just closes even when the probes are still connected.
I bet it's contacting servers to check for updates. Possibly verifying user login info if that is required to use it.
Good videos 😜
Everytime you get on your knees brother I hurt for you! Get you one of those kneeling pads from klien tools or one of those cheap one form Home Depot
Moving the temp clamps back and forth isn't always going to give you an accurate reading. I use a wire brush to clean the pipe if I have a abnormal readings before final diagnosis
Curtis I notice you use those field peace pressure gages and your phone alot . Do you really like those testers?
Probably is the TEV. If it were restricted a little more you’d also see that suction pressure drop’to a more reasonable level.
Can you not trynadjusting the superheat on the TEV body?
Was the txv wide open?
Yes
Why are HVAC service tech notorious for leaving old parts & pieces laying around after they’ve worked on a unit????? Just a pet peeve of mine after being in the HVAC business for over 50 years!!!!!
Was the sensing bulb mounted inside the cabinet ?. You would want it outside of the cabinet so you read proper Subcooling. That’s insulated of course. If it’s left inside the cabinet uninsulated your reading box temp.
sounds like youre sensing bulb has lsot SOME of its charge
👍👍👍
Those pressures were almost identical to the one I just left it was a trane dual pack. I installed a evaporator coil and I know I didn't get my txv to hot because I had it covered in heat block putty and a cold wet rag. Had a bad txv on startup just stuck open. Worst part is its for a guy on his death bed new txv won't be here till Wednesday. I offered to put a danfoss but advised it would void his warranty if he ever used another company and they wanted to throw a fuss. He decided to wait till Wednesday
Depending on TXV or orfice , only one matters!
Non adjustable txv? Could've gave it a turn
So what was it?
5kw is usually what sticks on, it negates 17000w or 1.5 ton of cooling. So, if you have a 3 ton, a TD of 10F would be expected. I still think compressor or txv. Either way, new drier 410A. You may have non-condensibles in the system too. No low balling.
I agree with you 💯
thermostat settings issues
👍
My two cents.. Low on refrigerant charge.. 1 sub-cool low... 2 Liquid pressures on the high side is Low of the outdoor temperature is above 86 to 90 degree F and the condenser coil is clean.
3 you need liquid refrigerant pressure on the TXV to force it open aswell as to produce the flash gas to expand in the evaporator for your sensing bulb to respond by closing the TXV to control the super heat... Add some refrigerant to bring up the sub-cool and let it run for some time and watch the suction pressure drop and your super heat rise.. Some feed back would be nice if possible.
Wrong 100 %
You are already flooding back with 1 deg superheat and you want to add refrigerant?? Do you even hvac?
When in doubt, sell new system lol
Put t xv bulb in ice water to see if superheat raises
I don’t think it’s TXV I would start by recovering refrigerant replacing filter dryer and use new refrigerant
just saying
What do you think it is? How do you justify this work to a customer? Sounds like a expensive gamble.
Because I don’t know if anyone work on it just before me and what did they do it I tell the customer this is what I need to do to start with
Or you think it is batter to start by changing parts TXV, then a compressor, ……….. either way repaire is going to be expensive
I had this thought too. You could pump down into a recovery cylinder and measure the pressure and temperature to verify the integrity of the existing refrigerant.
@@denrayr that would be a more reasonable approach. With the price of refrigerant these days, telling a customer to replace refrigerant on a gamble is rough.
That is a good point at least checking the refrigerant Dennis I agree we live in defiant times all you can do is give customer appreciations same Companies give you one option you need a new system collect the service fee and move on
Maybe it’s time to call blueon for support😊
Try pumping the unit down if it pumps down good n fast it's not the compressor. Replace the TXV, or install a piston, a good vacuum, new 410A.
I think it's the TXV
Cuties
You can use analog gauges and while it’s running disconnect the common wire on the condenser fan.
As the head Head pressure increases the The suction gauge should remain steady.
I saw this on the mentors RUclips channel.
TXV
Most txv fail closed. I’ve never seen a txv fail open. You have 2 closing forces internally to a txv with only 1 opening force (the bulb). So when the bulb loses its charge or doesn’t touch the pipe the valve loses its ability to open. Your pressures and temperatures indicate the valve open and unrestricted. It’s open because there is not enough liquid refrigerant to cool the suction line enough to force it closed. Clean your condenser coil and add some refrigerant. If you’re not comfortable adding refrigerant, recover what is in the system currently while weighing it as it comes out to verify your charge is correct.
I think the TXV is over feeding but you didn't take the compressor amperage to determine if it's weak or not. You need to know that.
Yank the sorry damn TXV out and put a piston in it.. Done and ya (NEVER) have to worry about it happening again, in fact with that being carrier, i would have just pumped it down, and got me a piston out, put it in, vacuum, takes 30 minutes on those bolt in deals..
A txv to piston isn't gonna change the seer rating much at all... Only difference is one meters flow off temperature and the other by orfice size. That's it the end!
If it's not a EEV, then it's not worth the time or trouble of installing! TXV's are the (WORST IDEAL) they ever came up with!!
Hell i bet i change 20 per year at (LEAST)!! Hell i have seen them go bad on systems less than 2yr old in fact!!
Weak compressor along with a weak fan. I would check the run caps as a low cost "just in case", but that system may not last another summer.
Txv
That's why piston systems are far better. Hate TXV's.
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For these txv's you need to have around 10° subcooling for them to meter properly. Make sure the sensing bulb is correctly placed, I would aim closely around the 7 or 5' O'clock position. And make sure the bulb is tightly wrapped. I use monkey shit. How this helps.
Your slugging back cause the liquid is flashing off, pushing the liquid. I have found that if your not over 3.7° SC you will have liquid flashing at AH.
Should’ve disconnected the sensing bulb and got hot or cold to see if the valve is really bad.
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I hate txv remove install piston body .u know ware your at with a piston
Dip the bulb in ice water wait 10 minutes if super heat stays the same bad valve