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  1. HVAC
    I have old Honeywell thermostat T874/Q674C with heat pump and baseboard heaters trying to wire it to RTH8500. On Q674C base are wires W1 - white W2 - black G - green Rc,Rh - connected together red B not connected O not connected Y2 not connected Y1 - yellow The manual for RTH8500 saying If...
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