Easy Heat Pump Question

brutis

I bought a new thermostat (LUX TX9000TS) which is a single heat pump thermostat. I have one unit on the side of my house so I assumed I have one heatpump. When I took the old thermostat off, one of the wires marked on it said "W2" which means 2 heat pumps to me which the new thermostat won't support.

I've been in this house only a year and have found many things done backwards but know nothing about HVAC. Is it possible for 1 unit to have 2 heat pumps? Or did someone do this backwards as well and just label the old thermostat wrong? Old thermostat is called "Apple's".

Old Thermostat: (Labeled on thermostat not on wires)
W2 - White wire
W1/0/B - Orange wire
Y1 - Yellow wire
G - Green
R - Red
C - Blue

New Thermostat Diagram
http://i151.photobucket.com/albums/s...uxTX9000TS.jpg

Any help appreciated, thanks.

Marvin Gardens

Do you have additional heat or cooling when it exceeds the capability of the heat pump?

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brutis

Not sure, how would I be able to tell if that is happening?

Marvin Gardens

Generally there would be a second unit nearby. You could also have a two stage heat pump.

If you feel comfortable with this you can open the side of the heat exchanger and see if that wire is connected to anything. Just use the color code.

It could be that the wire is just connected at the thermostat and not connected at the other end. I have seen that in the past.

A customer converts to a heat pump and the thermostat is never checked. They just hook up the wires that need to be hooked up to the unit to get it working.

Lazy, yes. Does it happen? More that one would think. When it comes to wiring of any kind I am never surprised about anything I find.

Although I must say that I have not seen anything weird in the last few years.

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bervin306

Yes you need to hook up the W2 wire. A heat pump has electric heat which is brought on when the heat pump can not maintain temp. It is also your emergency heat. The stat you have is not set up for 2 heat/ 1 cool it will not work properly on your system. If you hook it up your electric heat will not come on. You would need to get the Lux HP2110 stat. It is a heat pump stat. So by hooking up the w2 wire it will bring on you aux. heat when it gets to cold for just your heatpump handle.

beenthere

Wrong stat.

That stat is for HP's with NO Aux heat.

dac122

We could make an educated guess here, but without knowing how your old tstat is wired to your air handler and heat pump this isn't an Easy Heat Pump Question. If it was me I'd break out the volt meter and diagram how the entire system is wired end to end, and then map out what is hot during heating, secondary heating (if you have that), aux/em heat, fan only, cooling, and any other scenario.

If you wanna take some photos of how you're wired up and re-post we might be able to give you a better idea. Take photos with the old tstat in place, at the air handler and at the heat pump. Power the system off before doing that, try to tuck the wires out of the way so we can see what the label is on that terminal.