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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 6022
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a new AirTemp heat pump with terminals E, R, W2, C,

Customer Question

i have a new AirTemp heat pump with terminals E, R, W2, C, O,and Y. My existing furnace is a 10 year old Williamson oil furnace with terminals C, Y, G and R. I bought an Aprilaire 8448 thermostat and an outdoor sensor. Can you please tell me what terminals i need to use on the thermostat and where they connect on the heat pump? The way i have it wired, when i turn it to heat is automatically goes to Aux heat and the oil furnace turns on. it is about 45 degrees outside right now. Brad, Wheeling WV
Submitted: 1 year ago.
Category: HVAC
Expert:  Phil replied 1 year ago.


Look this over, your wire colors may vary a bit, we can discuss it, I will need a photo of the wire connections to the original thermostat and at the printed circuit card inside the blower cabinet.

Use the paper clip icon at the right end of the tool bar above to attach those.

We can go from there.