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  1. #1
    Join Date
    Jan 2006
    Posts
    56

    Cool Heat Pump 'reverse valve' check

    I have Limited repair work of Heat pumps over the years so a little assist needed please.

    One of our buildings we service has some Trane H/P with conventional 'totaline' digital stats. I don't have the model number with me but can post later if needed; I believe this particular unit is 3 tons.

    I would like to cycle the reverse valve at the unit to check its operation, and unit does not have the jumper test terminals for cycling unit through stages like some of the larger ones. I believe the R/V is energized during cooling, so would one simply remove the R/V wire from the H/P control/defrost board to open circuit to R/V thus initiating the heating sequence? Which would allow R/V valve observation?

    P.S. When adjusting temp at T-stat I was able to hear unit cycle to heating on roof above my head after about a 5 second delay, is this delay built into T-stat our H/P controller.
    Thanks for feedback...

  2. #2
    Join Date
    Oct 2003
    Location
    tidewater, va
    Posts
    2,135
    pull the plug on the rv and see if it goes into heat



    r404a

  3. #3
    Join Date
    Nov 2008
    Location
    Auckland New Zealand
    Posts
    56
    The delay time is built into the controller, I would carry out this test with the compressor contactor off because as soon as you pull that wire the reversing valve is going to de-energize and the last thing you want is that sudden change over without that 5min transition time. Compressors dont like that.

    Good luck

  4. #4
    Join Date
    Sep 2007
    Location
    Ohio
    Posts
    14
    how about residential heat pumps. They will run and slide into a defrost and that is what they are designed to do. compressor is running, discharge pressure is the same, it don't care where it goes.

  5. #5
    Join Date
    Jan 2004
    Location
    Lancaster PA
    Posts
    67,708
    Quote Originally Posted by kiwicontroller View Post
    The delay time is built into the controller, I would carry out this test with the compressor contactor off because as soon as you pull that wire the reversing valve is going to de-energize and the last thing you want is that sudden change over without that 5min transition time. Compressors dont like that.

    Good luck
    RV valves require the system to be running to switch from one mode to the next.
    The selenoid valve only switches which pilot line is pressurized.
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