I AM NOT LICENSED, CERTIFIED OR IN ANY OTHER WAY QUALIFIED TO PROVIDE ANY HEATING OR AIR CONDITIONING SYSTEM ADVICE. USE OF ANY OF THIS INFORMATION MAY CAUSE SERIOUS DAMAGE. CONSULT WITH A PROFESSIONAL BEFORE USING ANY INFORMATION ON THIS PAGE.
Really, I have very little knowledge of these systems and following the information here could cause great harm to your system. I consider myself lucky that I didn't blow up my entire heating and cooling system or burn the house down. I did do a lot of research and in the end, ended up deductively determining the new wiring based on all the information I could find. To this day, I'm still not sure if it's really correct, but so far, it seems to be working with my equipment. Also, this isn't a trial and error situation. I have no idea what happens if the power is turned on with the incorrect wiring, but I assume everything would get destroyed. Also, be careful with the old WeatherTron thermostat since it contains a mercury switch. Mercury is highly toxic and you don't ever want to be in contact with it.
Here's the setup:
- Electric Air Conditioner with Heat Pump Converter
- Emergency heat (furnace heat)
- Thermostat with cooling, regular heat and emergency heat.
 |  |
| Honeywell Programmable | Trane WeatherTron |
I couldn't find a Honeywell Thermostat that could handle multiple multiple heat sources at the local hardware stores, so I got mine, the "Honeywell TH8320U1008 7day 3/h 2/c Vision PRO 8000 Touchscreen Programmable Thermostat" from Amazon. It's a very nice thermostat and does everything I need. I also got the external temperature sensor for mine so it can automatically switch between electric and furnace heat, but I haven't installed that yet.
Before I tried anything, I made sure to TURN OFF THE POWER AT THE BREAKER for all heating/cooling equipment and to verify that the power is off everywhere using a field tester. Leaving the power on for the swap may cause serious damage or risk of shock or electrocution. Be very careful whenever working around electricity, especially if you're like me and aren't sure what you're doing.
Here's the original wiring for WeatherTron thermostat:
And the wiring I ended up with for the Honeywell:
One last final notice before the translation table:
CALL A PROFESSIONAL. DON'T TRY THIS YOURSELF. I AM NOT RESPONSIBLE FOR ANY LOSSES OR DAMAGES RESULTING FROM THE USE OF THIS INFORMATION.
| Wire Color | WeatherTron Terminals | Honeywell Terminals (Heat Pump Codes) |
|---|---|---|
| Red | R | R |
| Brown/Tan | T | * - Leave disconnected |
| Orange | O | O/B |
| Green | G | G |
| Yellow | Y | Y |
| Black | X2 | E |
| Blue | B | C |
| White | W | AUX |
* - I didn't hook the brown/tan wire up to anything. This wire should be taped or capped so it doesn't touch something else and cause a short.
Finally, if you get a new thermostat, don't just throw your old one in the garbage! The WeatherTron contains a mercury switch and needs to be disposed of properly. Find a place that can properly handle mercury disposal and let them take care of it. A lot of cities and counties have arrangements to take it for free and it's worth the trouble to not let mercury spill into the environment.
