New Mexico Whats the best way to set a thermostat for 2 stage systems.

Discussion in 'Maintenance and Troubleshooting' started by DMAXNM, Jan 30, 2017.


    DMAXNM New Member

    Hello I am new to this forum. I have question for anyone that can help. I am in the process of installing a new system. I purchased the 2 stage 5 ton water to air unit with no backup (electric/gas). I was wiring and configuring the thermostat and something came up. The thermostat has multiple settings to chose from. The two setting that I think should be able to be used are. The first is the 2H 2C. The problem have with that is the manual says to wire the 2nd stage of cold to Y2 and it says the 2nd stage of hot to the W2. The unit has one only one wire listed for a second stage witch is a orange wire, can these be jumper-ed together? The other option is the 3H 2C setting which says the 2nd stage is Y2 is for both. I have it configured this way now for testing and it does seam to work correctly. The only problem with this I see, is that it states the manual that stage 1 and 2 will shut off if 3 is turned on. I am hoping I am just miss understanding this. Is that true? Being that I don't have anything plugged in as a back up. I am guessing the system would shut down and I would have no heat. And of course that would only happen when its really cold. I would not want that to happen. So what would be the correct configuration? Thank you

    Oh and just as a side note: I do have back up in the form of a direct vent furnace and wood pellet stove. My plan is these are only needed or used during really cold days. They are set to turn on by there own thermostat and not be controlled by the geothermal.
  2. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    Make sure it is a heat pump compatible thermostat and it is set to heat pump.

    Y2 is second stage heat/cool. W2 is conventional but may be the same connection on the thermostat.

    DMAXNM New Member

    Thank you, The thermostat is a Pro 1 and is so posed to be compatible. As a mater of fact I did have to change a setting to get the heat pump to turn on. So if understand you right the second setting would be the better choice? The one using the Y2 only. I still do not have the duct work in place, so I have not really been able to test the system enough to get all the stages to come on correctly.
  4. weedy64

    weedy64 New Member

    Which model of Pro 1? Can you provide the model of heatpump or schematic for reference?

    In my PRO 1's when configured to Heat pump mode, Y1 is stage 1, Y2 is stage 2 for both heat and cool so an O or B wire needs to be utilized so the HP knows whether it is to be heating or cooling.

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