Results 1 to 12 of 12
  1. #1

    Confused Reversing Valve info

    In the home i recently purchased the heat pump has been faulty. When heat comes on sometimes immediately, sometimes after a few mins it will go to aux heat. Had a technician come check it out on the side. So he hooks up the gauges and he said the low side is ok but the high side the pressure was low. So he hooks a few things up and test it in HEAT only and the high side didnt rise, listening to it the pump sounds great just obviously isnt working correctly. so what he comes up with is a "busted valve" in the compressor. So I decide to do my research and see many cases of misdiagnosed compressor failure. so i took it upon myself to use an earth magnet on the reversing valve. ive watched a video of this done, my question/concern is that when changed from heat to cooling the magnet only pulls about a 1/2". and also if the magnet should pull towards the "center" of the valve when in heat or in cooling mode. If a video will help better I will post one so it can be seen. I truly hope this is a case of a sticking reversing valve.

    Thanks for any help!

    Trane XE 1000

  2. #2
    Join Date
    Jun 2007
    Location
    Greenwood Indiana (Indianapolis)
    Posts
    420
    The tech should of done a "pump down" test to see if the compressor valves are good. Generally, if the reversing valve is not shifting, there will be a loud hissing noise. The reversing valve and the compressor valves are two different things. Get a second opinion.
    As iron sharpens iron so one man sharpens another Proverbs 27:17 NIV84

  3. #3
    Join Date
    Jul 2009
    Location
    South Carolina
    Posts
    2,858
    The diagnosis between a compressor with bad valves & a bad reversing valve can be very difficult. Sometimes they can both be bad because a bad reversing valve can blow the valves on the compressor if it runs long enough. Forget about trying to diagnose it yourself & I agree that getting a second opinion is your best option.
    Gary
    -----------
    http://www.oceanhvac.com
    An engineer designs what he would never work on.
    A technician works on what he would never design.

  4. #4
    Not trying to diagnose the system myself, just figured i would try to test the reversing valve since its a somewhat straightforward process and to hopefully spare the expense of a compressor since i read every where that a bad compressor is commonly mistaken for a bad RV. No unusual noises at all throughout the whole system though. Also I did forget to mention that he did say the refrigerant was low as well, if that makes any difference in diagnosis.

  5. #5
    Join Date
    Jul 2009
    Location
    South Carolina
    Posts
    2,858
    Quote Originally Posted by xtreme89 View Post
    Not trying to diagnose the system myself, just figured i would try to test the reversing valve since its a somewhat straightforward process and to hopefully spare the expense of a compressor since i read every where that a bad compressor is commonly mistaken for a bad RV. No unusual noises at all throughout the whole system though. Also I did forget to mention that he did say the refrigerant was low as well, if that makes any difference in diagnosis.
    Not trying to be a smart ..$$ but it sounds like a contradiction. You're trying to diagnose a reversing valve which can be one of the most difficult parts to diagnose for even an experienced HVAC tech. The only reason a bad RV would be mistaken for a bad compressor is if it was stuck in the middle. Whatever magnet test you try may not tell you anything definitive. If the valve doesn't shift at all that's an easy dignosis but the symptoms are different than bad compressor, but a valve stuck in the middle is not an easy diagnosis especially when it could have already damaged the valves on the compressor. That's why I recommended getting a second opinion.
    Gary
    -----------
    http://www.oceanhvac.com
    An engineer designs what he would never work on.
    A technician works on what he would never design.

  6. #6
    Quote Originally Posted by garyed View Post
    Not trying to be a smart ..$$ but it sounds like a contradiction. You're trying to diagnose a reversing valve which can be one of the most difficult parts to diagnose for even an experienced HVAC tech. The only reason a bad RV would be mistaken for a bad compressor is if it was stuck in the middle. Whatever magnet test you try may not tell you anything definitive. If the valve doesn't shift at all that's an easy dignosis but the symptoms are different than bad compressor, but a valve stuck in the middle is not an easy diagnosis especially when it could have already damaged the valves on the compressor. That's why I recommended getting a second opinion.

    That answered any question i would have since it does shift the magnet.

  7. #7
    Join Date
    Jul 2009
    Location
    South Carolina
    Posts
    2,858
    Quote Originally Posted by xtreme89 View Post
    That answered any question i would have since it does shift the magnet.
    Again that is still not conclusive. It may be a positive sign for the RV being good but it can shift but not shift all the way & still get stuck in the middle where gas can bleed through. You've definitely done your due diligence so hopefully things will end up O.K.
    Gary
    -----------
    http://www.oceanhvac.com
    An engineer designs what he would never work on.
    A technician works on what he would never design.

  8. #8
    I see, i guess the last question would be if it doesn't shift completely, is a symptom of that POSSIBLY the high pressure not showing any increase with the heat pump running?

  9. #9
    Join Date
    Aug 2012
    Posts
    2,326
    In any case open your wallet and pay up. If you do have a bad comp. change the valve too. If the tech changes the comp. and the valve is bad then he can do that for cost I would think.
    Trying not to be a Hack.

  10. #10
    Join Date
    Aug 2012
    Posts
    2,326
    On second thought if he misdiagnosis a compressor you screwed.
    Trying not to be a Hack.

  11. #11
    Join Date
    Aug 2009
    Location
    Beatrice, NE
    Posts
    1,747
    The tech said the low side was ok, but the high side was low, so the compressor had bad valves? ? ? ?

    Bad compressor valves will present themselves with pressures that are off on both sides since gas is bypassing through the compressor valve(s).

    Find a better tech!

  12. #12
    Join Date
    Jul 2009
    Location
    South Carolina
    Posts
    2,858
    After rereading the first post I don't see where the system was checked in cooling mode which is a common practice before condemning the compressor valves on a heat pump. It doesn't mean the tech is wrong in his diagnosis, maybe he's a wizard & doesn't need to be that thorough. Either way, for the last time I say get a second opinion.
    Gary
    -----------
    http://www.oceanhvac.com
    An engineer designs what he would never work on.
    A technician works on what he would never design.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Comfortech Show Promo Image

Related Forums

Plumbing Talks | Contractor Magazine
Forums | Electrical Construction & Maintenance (EC&M) Magazine
Comfortech365 Virtual Event