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Thread: Low pressure drops instantly

  1. #1
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    Low pressure drops instantly

    Hello all. I'm new here and have an issue:
    Brand new condenser and air handler installed approximately 30 days ago. Standing Pressure at ambient temperature was 155. Condenser comes on and the low pressure drops all the way down and trips the LP cutoff. Would this be a TXV issue?
    thank you for responding/replying, Nick
    Last edited by Nickp276; 05-03-2021 at 05:19 PM. Reason: Forgot to say thank you for responding/replying

  2. #2
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    Itís a install problem

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  4. #3
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    I mean thereís not much to go off of here. You will need a technician to take measurements and gather data...thatís the ONLY way to make a diagnosis. If we guess at it weíre not really helping you. Do you have all of the data for this system while it is running?
    "I think Quantum tunneling would work great... "

    "Call a technician for God's sake. Or we'll see you on the news or the Dark Side of the Moon."

  5. #4
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    It sounds like a carrier/Payne/Bryant.

    Sent from the Okie state usin Tapatalk

  6. #5
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    Quote Originally Posted by R600a View Post
    It sounds like a carrier/Payne/Bryant.

    Sent from the Okie state usin Tapatalk
    So are they known for that? What fails on them?
    "I think Quantum tunneling would work great... "

    "Call a technician for God's sake. Or we'll see you on the news or the Dark Side of the Moon."

  7. #6
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    Quote Originally Posted by JayMan7 View Post
    So are they known for that? What fails on them?
    Some models have the TXV bulb connected to the suction line with a crimped metal band that cannot be removed without destroying it so when you braze the suction line it's extremely hard to keep it from overheating the bulb.
    What I don't understand is why is it a month later that the TXV goes bad. I'm 90% sure I overheated the TXV bulb but why didn't it show up immediately?
    I had that exact scenario on one of the last Payne units we installed. That's just one of the reasons that I like to refer to Payne as hemorrhoid. We don't always do things right at least not as right as we should but we have never had as many problems as we had with Payne for the 6 months we installed them.
    After a few months of constant callbacks on our installs I would take a Goodman or a Gree over a Payne.
    Oh yeah and the other thing that irks me is that the TXV, reversing valve and filter dryer are all Chinese along with most of the other components. If you buy a Goodman they contain twice as many american-made parts and for some reason I have very little problems from the goodmans that I run across in the field but the Payne's are nothing but a pain in the rear.
    I'll get off my soapbox now.
    Sent from the Okie state usin Tapatalk

  8. #7
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    Quote Originally Posted by R600a View Post
    Some models have the TXV bulb connected to the suction line with a crimped metal band that cannot be removed without destroying it so when you braze the suction line it's extremely hard to keep it from overheating the bulb.
    What I don't understand is why is it a month later that the TXV goes bad. I'm 90% sure I overheated the TXV bulb but why didn't it show up immediately?
    I had that exact scenario on one of the last Payne units we installed. That's just one of the reasons that I like to refer to Payne as hemorrhoid. We don't always do things right at least not as right as we should but we have never had as many problems as we had with Payne for the 6 months we installed them.
    After a few months of constant callbacks on our installs I would take a Goodman or a Gree over a Payne.
    Oh yeah and the other thing that irks me is that the TXV, reversing valve and filter dryer are all Chinese along with most of the other components. If you buy a Goodman they contain twice as many american-made parts and for some reason I have very little problems from the goodmans that I run across in the field but the Payne's are nothing but a pain in the rear.
    I'll get off my soapbox now.
    Sent from the Okie state usin Tapatalk
    Good lord man why donít the freaking enginerds that design this crap get a clue. I mean do they have no ability to think about things working in the real world.

    Speaking of txvs I wish I knew the percentage of txvs that fail because the bulb loses charge. Maybe thatís what happens on the paynes. The bulb develops a super small internal leak in the powerhead because of shitty manufacturing and it takes about 6mo to leak out. Itís such a small amount of refrigerant in those bulbs. I mean you could have a situation where a few molecules leak out at time and it wouldnít take long to be out.
    "I think Quantum tunneling would work great... "

    "Call a technician for God's sake. Or we'll see you on the news or the Dark Side of the Moon."

  9. #8
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    Quote Originally Posted by JayMan7 View Post
    Good lord man why donít the freaking enginerds that design this crap get a clue. I mean do they have no ability to think about things working in the real world.

    Speaking of txvs I wish I knew the percentage of txvs that fail because the bulb loses charge. Maybe thatís what happens on the paynes. The bulb develops a super small internal leak in the powerhead because of shitty manufacturing and it takes about 6mo to leak out. Itís such a small amount of refrigerant in those bulbs. I mean you could have a situation where a few molecules leak out at time and it wouldnít take long to be out.
    It always looks strange to me that the little tube stub that they fill it through is just pinched off and not soldered or anything. It always makes me want to hit it with sta brite 8.

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  11. #9
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    Quote Originally Posted by R600a View Post
    Some models have the TXV bulb connected to the suction line with a crimped metal band that cannot be removed without destroying it so when you braze the suction line it's extremely hard to keep it from overheating the bulb.
    What I don't understand is why is it a month later that the TXV goes bad. I'm 90% sure I overheated the TXV bulb but why didn't it show up immediately?
    I had that exact scenario on one of the last Payne units we installed. That's just one of the reasons that I like to refer to Payne as hemorrhoid. We don't always do things right at least not as right as we should but we have never had as many problems as we had with Payne for the 6 months we installed them.
    After a few months of constant callbacks on our installs I would take a Goodman or a Gree over a Payne.
    Oh yeah and the other thing that irks me is that the TXV, reversing valve and filter dryer are all Chinese along with most of the other components. If you buy a Goodman they contain twice as many american-made parts and for some reason I have very little problems from the goodmans that I run across in the field but the Payne's are nothing but a pain in the rear.
    I'll get off my soapbox now.
    Sent from the Okie state usin Tapatalk
    Sounds like an installer problem instead of equipment problems. Try a wet rag wrapped around the coil side of where your brazeing

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    Quote Originally Posted by oldguy1949 View Post
    Sounds like an installer problem instead of equipment problems. Try a wet rag wrapped around the coil side of where your brazeing
    I did. The true fix for us was switching to a brand that used a decent strap. That was one of the more minor problems. The doa compressor and the lack of hail guards or pressure switch is what really bothers me. In Oklahoma if a unit doesn't have hail guards it won't last 10 years.

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  13. #11
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    It is a 3 ton 16 SEER American Standard condenser and a 3 ton First Co air handler (exactly what was originally there).
    When the piping was brazed at the air handler the TXV sensing bulb was removed from the pipe to avoid any issues.
    The vacuum got down to 300 microns before the system was opened up. I added the additional refrigerant it needed for piping beyond the 15 feet.

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  15. #12
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    Once the system comes on the low pressure drops within 5 seconds so I'm unable to get any kind of readings other than what I provided.
    It is a 3 ton 16 SEER American Standard condenser and a 3 ton First Co air handler (exactly what was originally there).
    When the piping was brazed at the air handler the TXV sensing bulb was removed from the pipe to avoid any issues.
    The vacuum got down to 300 microns before the system was opened up. I added the additional refrigerant it needed for piping beyond the 15 feet.

  16. #13
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    You can either suck out the freon and weigh it , and compare to the factory charge specs ... to tell you if there is a leak

    Or dump a couple pounds in there and see what happens

    But if this worked for 30 days and quit all of the sudden , its either a big leak , or the TXV gave up , or the screen is somehow full of crap ( doubt that )

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  18. #14
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    Quote Originally Posted by R600a View Post
    It always looks strange to me that the little tube stub that they fill it through is just pinched off and not soldered or anything. It always makes me want to hit it with sta brite 8.

    Sent from the Okie state usin Tapatalk
    Iíve always wondered why that was just pinched off and not sealed the way we would figure it should be. I do however have a theory on a new install why the valves can fail. I think sometimes it has to do with that stub just being pinched off. If somebody doesnít take precautions like wrapping the bulb or taking it off the line, I think the heat from welding gets it so hot and the refrigerant pressure in the bulb get high enough that itíll push some of it out of that little stub. I have no way of proving that other than maybe try welding one up with the coil door off and your leak detector right at that stub and see if it picks anything up. Iím not sure if thatís even in the ballpark of reality or if that is way off in the back 40 but I donít see why itís not possible. Most failures are from not flowing nitro and that crap gets into the valve but we all know that one so I just like to try to come up with other possibilities.

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  20. #15
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    I did that on Saturday and it was all good to go. Even replaced the filter drier too, did a nitrogen leak test, vacuum down to 300 microns and it was still dropping. Not sure if it worked at all, it was installed while still cold out and not ran until a hot day about a week ago. The home owner reached out to me asking about it.

  21. #16
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    Quote Originally Posted by R600a View Post
    Some models have the TXV bulb connected to the suction line with a crimped metal band that cannot be removed without destroying it so when you braze the suction line it's extremely hard to keep it from overheating the bulb.
    Yeah I just did 2 carriers last week and had to carefully pull off the tiny little cheesy ass piece of insulation they have wrapped around the bulb , then shoved a wet rag around the bulb/suction pipe , worked out just fine.

    Then getting the little cheesy ass insulation back around it was fun

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  23. #17
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    Quote Originally Posted by Snapperhead View Post
    Yeah I just did 2 carriers last week and had to carefully pull off the tiny little cheesy ass piece of insulation they have wrapped around the bulb , then shoved a wet rag around the bulb/suction pipe , worked out just fine.

    Then getting the little cheesy ass insulation back around it was fun
    Yeah I just tear it off throw it away and replace it with my own roll of armaflex tape. It's possible I've been blaming myself for the death of a TXV when reality it was just a crappy TXV. I will say there wasn't much to like about that equipment. The pop outs just about had to be drilled out because they weren't really cut like they're supposed to be from the factory and the coils were not a good design and then the txvs were sometimes cramped on and always a pain in the neck to get to because the coils were so cramped. I don't miss them at all. Our new line is Armstrong and they are so much nicer. Although the biggest plus with Armstrong is that the distributor is amazing whereas the carrier distributor was not.
    I really didn't mean to distract from the OP so much.
    It sounds like his troubles are not related to my experience.
    I will mosy on over to the no more Payne thread and keep cheering for the demise of Payne. ,
    Sent from the Okie state usin Tapatalk

  24. #18
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    Quote Originally Posted by Nickp276 View Post
    I did that on Saturday and it was all good to go. Even replaced the filter drier too, did a nitrogen leak test, vacuum down to 300 microns and it was still dropping. Not sure if it worked at all, it was installed while still cold out and not ran until a hot day about a week ago. The home owner reached out to me asking about it.
    Which post were you replying to? It's hard to tell what you're saying that you did on saturday.

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  25. #19
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    Quote Originally Posted by Snapperhead View Post
    Yeah I just did 2 carriers last week and had to carefully pull off the tiny little cheesy ass piece of insulation they have wrapped around the bulb , then shoved a wet rag around the bulb/suction pipe , worked out just fine.

    Then getting the little cheesy ass insulation back around it was fun
    Stay bright 8 and mapp gas. Donít worry about over heating again.


    Sent from my iPhone using Tapatalk

  26. #20
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    Quote Originally Posted by jbhenergy View Post
    Stay bright 8 and mapp gas. Don’t worry about over heating again.
    When 410a first came out I did a whole system with staybrite , still kicking along today

    These last 2 I did were in an attic thats a mother to get to , and I didnt wanna chance leaks

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