I replaced an old mercury switch thermostat
with a new Honeywell RTH6580WF and connected the wires according to the 'heat pump' directions in the Honeywell manual. I have a Carrier
Model 40AQ03000BB (Inside) 38QN030331SM (outside)
There are eight wires and they were connected to the following areas on the mercury thermostat:
Orange to O
White to W2
Black to C
Tan to L
Yellow to Y
Red to R
Green to G
Blue to E
Based on the directions in the manual, I connected the wires this way:
Old Connection/Color/New Connection
When I turn on the cool function (Inside temp reads 80 and thermostat set for 75) the heat kicks in and hot air comes out of the vents - even though the thermostat display reads 'cool on.' I tried the opposite - set it to heat and set the temperature to 85 but nothing happened. I am able to turn the fan on manually from the thermostat but can not get the thermostat to turn on the A/C.
Other than not being able to control the temperature, the thermostat works fine. Registered the unit and connected to the WiFi with no issues.
After reading about others with older units and this thermostat, I disconnected the blue wire (E) completely from the thermostat, but there was no change in the function - trying to cool still blows out hot air and trying to heat does nothing.
I tried calling the Honeywell help desk but after listening to the 'all of our operators are busy' message for 30 minutes I figured they are closed for the holiday.
Any thoughts or ideas on how to wire this thermostat so it will work with my system will be greatly appreciated.