I recently installed a honeywell rth7500 thermostat and am not sure if it is correct. The old thermostat is a GE, not sure how old. I have a heatpump system (Goodman A61-20) I wired it as follows:
Old R(red)- new R
Old O(orange) - new O/B
Old G(green) - new G
Old Y(yellow) - new Y
Old B(blue) - new C
Old U (black) - new E
Old W (white) - new AUX

I attached the U lead (black wire) to the new E connection because the system uses emergency heat and was the only wire not accounted for.

System has been operating for about 1 month. In the last couple of days, the outside temp has been below freezing and system was not keeping up the proper temp inside. (set at 68, got down to 58) One of the circuit breakers on the unit kept tripping, don't know if overloaded or wired incorrectly. It seems as if the emergency/auxillary heat element doesn't run properly.

Thanks

What kind of aux. heat do you have <gas or electric furnace?, when it gets down pretty cold(usually 35 or around that) your systen depends more and more on the aux. heat, sounds like that's where the prob. Might be,, if you set tstat to emergancy heat does the furnace work OK alone?

The heat pumps that I have delt with have had a thermostat in the heat pump that switches the heat pump off at around 35 degrees and makes it so that only the emergency heat will operate.
If you have electric heat it is possible that you have a bad heating coil in the heat strips above the air handler, this could also acount for the blown fuse.

I recently installed a honeywell rth7500 thermostat and am not sure if it is correct. The old thermostat is a GE, not sure how old. I have a heatpump system (Goodman A61-20) I wired it as follows:
old R(red)- new R
old O(orange) - new O/B
old G(green) - new G
old Y(yellow) - new Y
old B(blue) - new C
old U (black) - new E
old W (white) - new AUX

I attached the U lead (black wire) to the new E connection because the system uses emergency heat and was the only wire not accounted for.



System has been operating for about 1 month. In the last couple of days, the outside temp has been below freezing and system was not keeping up the proper temp inside. (set at 68, got down to 58) One of the circuit breakers on the unit kept tripping, don't know if overloaded or wired incorrectly. It seems as if the emergency/auxillary heat element doesn't run properly.

Thanks


Here is a old chart for wire conversion. This might help you in the conversion checking from the GE/Bay stat setup to the new Honeywell.

You will see that the old GE system used the B (black) wire for a leg of the 24 volts. Usually I will admit the wire colors are not as important as writing down what color went to what post or terminal on the old thermostat for the conversion.