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    tr7man's Avatar
    tr7man Posts: 2, Reputation: 1
    New Member
    		  
    #1

    May 18, 2008, 11:00 AM
    How to wire a new thermostat
    I have an old Robertshaw thermostat, replacing it with a honeywell rth221b, the problem is the wiring doesn't match. On the Robertshaw I have 4 wires, white - O red to Rc, yellow to W and Y, green to G. On the honeywell, there is no O and the w and y are on two separate terminals, I only have the one yellow wire. Anyone have a clue? Thanks
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
    		  
    #2

    May 18, 2008, 12:29 PM
    What kind of unit? Heat pump? Gas furnace? Electric furnace?
    tr7man's Avatar
    tr7man Posts: 2, Reputation: 1
    New Member
    		  
    #3

    May 19, 2008, 08:55 AM
    Quote Originally Posted by tr7man
    I have an old Robertshaw thermostat, replacing it with a honeywell rth221b, the problem is the wiring doesn't match. On the Robertshaw I have 4 wires, white - O red to Rc, yellow to W and Y, green to G. On the honeywell, there is no O and the w and y are on two separate terminals, I only have the one yellow wire. Anyone have a clue? Thanks
    I found my error, I bought the wrong thermostat, when you replyed heatpump I look at what I bought and it's for electric AC only.
    Thanks
    hvac1000's Avatar
    hvac1000 Posts: 14,540, Reputation: 435
    Heating & Air Conditioning Expert
    		  
    #4

    May 19, 2008, 09:07 AM
    Glad you found the problem.
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