I just bought new programmable z-wave thermostats (Honeywell TH8320ZW). I thought I had the wired correctly, but I woke up to a pretty chilly house this morning. The fan is working, but it seems to be blowing cool air. Here is a picture of the original wiring for the upstairs thermostat: Original Wiring

Full disclosure: A year ago, I replaced this thermostat, but realized I had ordered the wrong thermostat, so I put the old one back. There is an outside chance that I wired it back incorrectly, but that would not be typical of me; also I have not noticed it not working properly.

Here is a picture of the new thermostat wiring as I have done it: My new thermostat wiring

Can someone help me figure out what I did wrong?

OK, I figured out part of my problem, but it presents another question. I have not configured the thermostat (I know stupid mistake, but in my defense those pages were stuck together in my manual). However, there does not appear to be a configuration in the manual that matches my wires. The closest appears to be 2H/1C Heat Pump (with aux heat). If I am correct, and reading the foot notes correct, I need a jumper between E & Aux, and the L is optional. Am I correct? Manual

  • 1
    Are the settings on the thermostat right? If it's like mine, there are 'advanced settings' included that have to be set. Read the manual again and double check these as the wires look right.
    – TFK
    Feb 13, 2016 at 16:51
  • I just edited my question literally 30 seconds before you posted. No, I had not fixed the advanced settings, but none of the settings appear to match my wires.
    – Andrew
    Feb 13, 2016 at 16:53
  • You should also verify the wiring by looking at the wiring on the control board in the furnace. There's no actual standard for wire colors, so you can't make any assumptions based on colors. Once you know that, it's likely a matter of ensuring the colors go to corresponding terminals on both sides, and the thermostat is configured properly for your setup.
    – gregmac
    Jun 6, 2017 at 16:41

2 Answers 2


2H/1C Heat Pump (with aux heat) seems like the correct option, as it sounds like you have a heat pump and a secondary heat source (furnace, etc.).

The jumper between E and AUX makes it so that if the thermostat calls for emergency heat, the second heat source will be used instead.


I'm not an HVAC expert but two things that occur to me is that you don't have the blue wire in the first pic going to B which I think it should. The second is that you should be able to take the panel off your air handler and look at how the wires go to its control board. On mine the control board is labeled the same way as the thermostat so you can probably check your work that way.

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