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  1. #1
    Join Date
    Jul 2012
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    Controlling Maytag Q5RF X36k heat pump -- 2 stage cooling, compatible thermostat, etc

    Goal: Get a compatible programmable thermostat and know my system better.


    Tried in vain to get help from Maytag or local company so coming here ;-0

    I almost positive my Maytag Q5RF X36F has 2 stage cooling and heating, plus aux heat.

    The original tech wired up a non-programmable honeywell TH532OU1001. He wired up C, O, W2, Y, Y2, RH/RC (jumpered), and G. There was a black wire that was unused. The original tech is out of business so I can't get with him :-(


    1) Does my unit have 2 stage cooling, 2 stage heating (via the same compressor) AND aux heat as well (via elec coil)? I know it does have the elec coil backup heat in it.

    2) What happens if I use a thermostat that does, for heat pump application, 1 stage cooling + 1 stage heat + aux heat? What does the compressor do in cooling mode, only run at half capacity (e.g. could it be having a lot of trouble keeping up in the hot summer), or does it run at full and just cannot go to half? (I put in a programmable thermostat but I don't think it's made for heat pump application where there is 2 stage heating and 2 stage cooling.)

    3) Last, what programmable thermostats would work with my system? I just can't find clear literature on heat pump application for 2 stage cooling, 2 stage heating (if I have that), + aux heat.


  2. #2
    Join Date
    Jul 2012
    Northern NY
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    Not familiar with your physical hardware but based on the point you have wired up you have a 2-stage heat pup with reversing valve and a an auxiliary heat system (I believe you say it is electric)

    G-Fan control
    Y-Compressor Stage 1
    Y2-Compressor Stage 2
    W2-Auxilary heat
    O-Reversing Valve
    C-24VAC Common
    RH/RC-24VAC Positive

    1) It appears you have 2 stages and this can either be accomplished by 2 physical compressors in the unit or sometimes 1 compressor and 2 speeds/stage built-in. These same physical stages run in either heating or cooling mode and the reversing valve (O) switches whether it heats of cools the supply air.

    2) You would only use 1 stage of the compressor and you heating & cooling capacity would be reduced so I high demand days you may not be able to keep the space at temperature.

    3) Any 2 stage heat pump thermostat would work, there are many brands available just depends on your needs.

    A quick search of Kele bring up this programmable stat

    but others are available


  3. #3
    Join Date
    Jul 2012
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    Thread Starter
    Thanks much...I appreciate the help!


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