How to wire Honeywell RTH7600D

I just bought a Honeywell RTH7600D to replace a Maple Chase 09620 which is old and starting to flake out. The Maple Chase is wired as follows:

White --> C
Red --> R
Orange --> Y2
Yellow --> Y1
Blue --> E
Green --> G
Tan --> W2
Black --> O

The problem is that on the Honeywell, E and W2 are the same terminal. I called Honeywell, they said my system is a 3h/2c system and this t-stat would not work, I would have to get one of the pro install models like the TH8000 series. So I looked at the install manual for the TH8320, but the E and W2 are again the same terminal. How do I wire this?

FWIW, our primary heat is an oil fired baseboard radiator system on a separate t-stat. The heat pump/air conditioner is for heat backup in case we run out of oil, and cooling in the summer, of course. We just moved in recently and I am not sure of all the system specs. HOWEVER, I am not convinced the system is working properly or maybe it's wired incorrectly - because it doesn't seem like it has auxiliary/emergency heat. One time in December we were running low on oil so I turned off the oil burner and just ran the heat pump until we could get the tanks filled. One night it got below freezing and you would have thought I was running the air conditioner instead of the heat, it was 50 degrees in the house by morning. Seems like aux heat would keep it warmer than that.

Comments? Thanks!

KES

 

are you sure you have aux heat? You need to check your air handler to be sure. Just because the stat is wired as though you do have aux heat does not actually mean you do.

What is the rest of the model number of your thermostat. I know Honeywell was going to stop separating E and Aux, but I have not sen one that has had this change yet. Make sure you are using the heat pump terminal designations and not the conventional. Post a picture of your thermostat connections for the new stat if you would please.