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  1. #1
    Join Date
    Aug 2018
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    TEV Check Valves

    Full disclosure, Ive only seen a couple of heat pumps in my career thus far. My region routinley touches -5F to 5F for three months of the year.

    Few week old call. Found low to no superheat on 3 ton goodman split system. Tried adjusting with absolutely no change. Condemened TEV and ordered like for like. After replacing and starting up find internal check in old valve which didnt seem to seat properly with some mouth to mouth. Put a few psi on the inlet and it did leak through.

    New valve has a check. Pissed that I missed it. I cant even understand how or why that valve wouldve been installed in my area. Frustrating given that it isnt a heat pump. Im sure the new valve will perform for years.

    Does oil flowing through circuit assist in seating the valve?

    If not, how likely would the check have been the cause of compressor flooding?

    Is this a common problem with heat pumps TEVs?

    Thanks in advance.



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  2. #2
    Join Date
    Apr 2003
    Location
    St. Louis
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    636
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    Never seen a check on a tev.

  3. #3
    Join Date
    Aug 2018
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    Thread Starter
    Its for reversal of flow so that the high pressure liquid leaving the indoor coil in heating flows through the check in the body of the TEV instead of the oriface and seat.

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  4. #4
    Join Date
    Dec 2014
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    Someone sold a heatpump coil with a straight AC maybe? With a plan to change to htpmp but never did? Maybe.?

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  5. #5
    Join Date
    Aug 2018
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    Thread Starter
    Maybe, looked to be the original valve. System installed in 2004-05. I don't believe our local dealer would've have made that mistake.

    I see no issue with leaving this valve in place just kicking myself that I wasn't paying close enough attention. More so I am just curious whether that kind of failure occurs.

    I do believe that the valve sticking was the issue, being that adjustments made no difference, but I'm curious whether the check would've contibuted to low superheat. Could it do so to the point where so much liquid is passing through the check and not the TXV? In everyone's experience have they found this often or not at all.

    I assume oil in the system assists the check in sealing and once I had it out it would tend to leak, but I'm just curious whether anyone could confirm it.

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  6. #6
    Join Date
    Dec 2012
    Location
    columbus, OH
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    Ive seen txvs over feed. Never determined the cause of it but i suppose that could be it. No it is not a very common issue even in heatpump territory.

    I cant say for sure but suspect it accompanies txvs that have a wide range of operation like 1.5 to 5 tons or 8-12. Ive gathered that newer txvs have a wider range than of days past. It would be impossible for a specific capacity txv to overfeed by much unless a really low load was present or as you said an internal bypass was stuck.


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  7. #7
    Join Date
    Dec 2012
    Location
    columbus, OH
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    Btw i dont believe check valve would be the proper term.


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  8. #8
    Join Date
    Dec 2014
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    I did have one instance of a checkvalve sticking on a heatpump. Flooded out the pump. Changed the pump and it showed up. Pinched the line and it ran good. (In AC mode only lol) changed the check and good to go!

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  9. #9
    Join Date
    Aug 2018
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    Thread Starter
    I guess only way to know for sure would be to somehow seal off the bypass port and reinstall the valve (not doing that). Will note that correction of the language core_d.

    Just a little curious... thanks for the info.

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