View Full Version : OT-Please check my Thermostat wiring diagram

Ron of Va
12-08-2010, 05:42 PM
Last summer I installed a heat pump in my shop. The AC works fine, but when I turn the thermostat to heat, the Aux light comes on and I get heat. When I turned it to emergency heat, I get no heat at all. I am now questioning how I wired the thermostat/air handler/heat pump.

Any experts out there that can look over my diagram and see any obvious mistakes?

12-08-2010, 07:09 PM
Was that the way the diagram that came with the unit is? I would guess each maker would have different ways but the wires coming to the thermostat control would be standard. There has to be a standard wiring for the thermostat regardless of which brand thermostat is used, the heat pump/furnace is another matter.

Ron of Va
12-08-2010, 07:34 PM
My son replaced his entire unit because he thought it was undersized. He called me when the job was finished, and asked me if I wanted the old unit for my shop. I got it as three pieces. Air handler, outside unit, and thermostat. I know it was working when I got it.

I did the best I could wiring the unit, but I am now thinking the “E” connection on the thermostat probably means “emergency heat”. I am not sure it is wired correctly.

12-08-2010, 07:38 PM
You may be right on the E part. Is there a diagram inside the indoor unit somewhere? Most have one there. Did he have a manual for it? There may be an online diagram.

Ron of Va
12-08-2010, 07:45 PM
There is a diagram, but it is mostly unreadable. It is not much help.

12-08-2010, 09:14 PM
Call the manufacturer, ask them for a copy of the wiring diagram. There is also the internet and or email. If you can't get any info from them, email me the information with a picture of the unit and thermostat as well as any information you have. Make, model, etc. I can see what info i can get.

Just one catch. I am pretty busy right now so it won't be instantaneous.

Rob :)

12-08-2010, 09:36 PM
http://www.diychatroom.com/f17/heat-pump-thermostat-help-89020/ see if this is any help

Ron of Va
12-09-2010, 11:55 AM
Thank you very much for the feedback.
The wiring diagram wasn’t as bad as I had remembered. Here is a section that shows some of the wiring that I think might be germane to the question.
My outdoor unit does not have an “E” or an “L”.
I just connected the E at the thermostat to the E at the Air Handler, and it did not make any difference. I connected a jumper wire from the E to the W2 in the Air Handler, and it did not make any difference.

The Air Handler is a Carrier, Model 40AQ03300BU
Heat pump is an Amana, model VHA24B2A
BTW, With the addition of the E, I am out of thermostat wires to use.