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  1. #1
    Join Date
    Mar 2005
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    My Tappan Heat Pump is not shutting down on heat cycle when temperature is reached. The original thermostat was long ago changed out with an Honeywell Heatpump thermostat. It didn't seem to work properly as aforementioned. We purchased a new White-Rogers Heat pump thermostat and are not sure where all wires should be landed. The Heat pump is agreeably a older Tappan (Model PHR 24-41 T). The thermostat wires are landed at a gang lug at the heat pump unit as follows.

    C =
    Y = Yellow
    W1 = White
    W2 = Brown
    R = Red
    G = Green
    O =

    The White-Rogers Heat Pump Thermostat has the following lugs.


    Logically if one follows the wiring scheme from the unit.

    Then the only wire that would seem to be in limbo would be
    the White thermostat wire since there is no W1 lug on the White Rogers Thermostat....Where does the white wire get landed on the thermostat ?

  2. #2
    Join Date
    May 2000
    Indianapolis, IN, USA
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    Good question. A tech will have to see where it goes.

    Since there is no wire currently used on 0 which tells the heat pump whether to heat or cool, they may be using an old Lennox method of using W1 as 1st stage compressor in heat mode. The signal went to a latching relay to tell the reversing valve what to do and also bring on the compressor. I wouldn't mess with it until you figure out where W1 goes and why nothing is on O.

    That relic is beyond my Honeywell heat pump cross reference book.

  3. #3
    Join Date
    Feb 2004
    cocoa fl
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    becareful not to fix and or brake anything you no little about. i would call a tech to come take a look at it before you have no heating or cooling and a large bill to get it back up and running.

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