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Termostat wiring (4 wires with orange??)

Posted by cujosocal (My Page) on
Tue, Jun 7, 11 at 23:03

After researching, it seems the normal color coding for a 4 wire system is R,G,Y,W... I don't have a white wire, appears to be orange instead! I have a Hunter 44110 that is replacing an old thermostat. The new unit had the folowing terminals: Rc/Rh (jumpered), G, Y, W,... So i hooked the wires up accordingly and hooking the orange to W (assuming they used orange wire instead of white)... turned the unit on and adjusted the temp on the thermostat. A/C seemed to kick in normally, but all that came out of the vents was warm air. I even waited a few minutes thinking it was just the residual warm air in the ducts. Any ideas of what went wrong??

Thanks!


Follow-Up Postings:

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RE: Termostat wiring (4 wires with orange??)

Below is a link which may help you.

Do you have a heat pump? An orange wire is usually the reversing valve for a heat pump. Connecting it to the W terminal is not going to work.

If you do have a heat pump, then check to see if your thermostat is compatible.

Here is a link that might be useful: Thermostat wiring


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RE: Termostat wiring (4 wires with orange??)

How can I tell if I have a heat pump? We're renting a duplex in AZ. The entire unit is on the roof...


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RE: Termostat wiring (4 wires with orange??)

what colors were connected to which screws on the old thermostat?

Red is power, Green is Fan, Yellow is 'turn on compressor' (for a heat pump, anyway), White is heat. There will be another wire for the reversing valve for a heat pump. Which probably doesn't matter since the Hunter 44110 doesn't support a heat pump.


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RE: Termostat wiring (4 wires with orange??)

The old thermostat had exactly the same colored terminals as the wires... R,Y,G,O

I doubt I have a heat pump. The house is all electric.


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RE: Termostat wiring (4 wires with orange??)

If the unit is all electric, then it is highly likely you have a heat pump. The other possibilites would be an electric furnace or resistance baseboard heat.

Do you have the model number of the old thermostat? If yes, then do a Google search and see if it is compatible with a heat pump. If it is, you need to exchange the Hunter 44110 for another model.


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RE: Termostat wiring (4 wires with orange??)

I can't find a manufacture label on the unit... I think it was taken off and the service company put their own tag on it.

Assuming I do have a heat pump. Would it make sense to only have these 4 wires (and no white) mentioned for both heating and cooling??


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RE: Termostat wiring (4 wires with orange??)

For everything I have read, yes it makes sense that the orange wire replaces the white wire for a heat pump configuration.

The white wire is used to turn on the furnace for heat, and the yellow wire enables the condenser for cooling. But you have a heat pump, therefore when you are in heating mode, the thermostat will turn on the condenser (yellow), but it must also enable the reversing valve in the proper direction. The orange wire is used to control the reversing valve.

Call the Hunter technical support line at 1-888-830-1326 from 8am to 5pm Central time. They should be able to review this with you and guide on which thermostat is appropriate for your set up.


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RE: Termostat wiring (4 wires with orange??)

Did the colored terminals on the old Tstat have labels? if so, what?


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RE: Termostat wiring (4 wires with orange??)

@weedmeister:

Yes... as mentioned above "The old thermostat had exactly the same colored terminals as the wires... R,Y,G,O"... (colored terminals=labeling)


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RE: Termostat wiring (4 wires with orange??)

So the old tstat had an "O" and a "W", and the Orange was connected to "O"? Then, yes this is a heat pump thermostat and you need to go get a different one than that Hunter.

Usually Heat Pumps also have Aux Heat. But you would probably never use it in Phoenix, and hence it may not be connected (W). Heat is activated by the reversing valve (O) which reverses the flow of the refrigerant through the system.


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RE: Termostat wiring (4 wires with orange??)

So it turns out I do have a heat pump! I exchanged my thermostat for one that supports a heat pump (3M Filtrete). It had connections for all 4 colored wires. Works perfectly!

Thanks for all the help!


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RE: Termostat wiring (4 wires with orange??)

I'm glad you got this resolved. Enjoy your new thermostat.


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RE: Termostat wiring (4 wires with orange??)

And thanks for coming back and reporting the outcome.


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