Wiring for Thermostat with Heat Pump - http://www.hvacmechanic.com/ Forums
Original message
| fredhag
 |  "Wiring for Thermostat with Heat Pump"
, posted Sun 19 Oct 16:04  
I recently bought a programmable thermostat to replace an old one in a house I just bought, and I'm wondering about the wiring (please help). The new thermostat is a Hunter (44260) that supports single stage heat pumps (yeah, I've since read how bad Hunters are). Anyhow, it has:
Rh/Rc
G(fan)
Y/O (AC compressor or reversing valve operation in cool mode)
W/B (heating or reversing valve operating in heat mode)
Y1 (heat pump compressor)
The inside unit is an electric Mor-Flo vertical fan coil unit (VH-HAC series, 6510075) with just R, W, Y, and G.
The (outdoor unit) heat pump is a Ducane and has the following wiring:
Y (compressor) - Connect to Y1 on stat?
C (common) - this was connected to Y on the inside unit -- does that make sense? If so, what should it be connected to on stat if anything?
G (fan) - this was not connected to anything (should it be?)
R - connected to R on inside unit so I put it on R on stat.
O (reversing valve) - Connect to O on stat?
W - connected to W on inside unit so should it be connected to W/B on stat?
This leaves the inside unit. R and W are connected as mentioned above to R and W on stat. Also G is connected to G on stat. This leaves Y as mentioned above.
In summary, I am wondering if the C (heat pump) should be connected to Y on inside unit and what on the stat? Also, should I connected G on outside unit to G on stat or leave it alone since it has been connected?
Another way of looking at this whole mess is to assume that wiring to the old stat was basically correct. The old stat was for a multi stage heat pump that must have been replaced. There were lots of wires connected at the stat but not in the HVAC room. Those that were connected are: R, Y, G, W, O, and B. If I just keep the same wiring, then I'm assuming Y on the old stat goes to Y1 on the new one, and then I'm not sure about O and B. I imagine O goes to Y/O (joining the Y from the outside unit). B on the old stat was connected to Y on the inside unit and C on the outdoor unit. Would they go to W/B on the new stat?
Thanks.
Cheers
Fred
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Replies:
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| bama 101
| "Re(1):Wiring for Thermostat with Heat Pump" , posted Sun 19 Oct 16:46
carry the thermostat back and get a heatpump thermostat with two stage heat
Help is just a question away.
Safety is up to you....
....THINK........
....Safety........
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| | fredhag
| "Re(2):Wiring for Thermostat with Heat Pump" , posted Sun 19 Oct 16:50
Thanks for the reply.
I saw nothing that it's a two stage and haven't seen any auxiliary or emergency heating kinds of things. Even if it is a two-stage, can it be wired without 2nd stage?
Cheers
Fred
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| | bama 101
| "Re(3):Wiring for Thermostat with Heat Pump" , posted Sun 19 Oct 17:12
no if you want it to work correct
Help is just a question away.
Safety is up to you....
....THINK........
....Safety........
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| | fredhag
| "Re(4):Wiring for Thermostat with Heat Pump" , posted Tue 21 Oct 05:08
I got a Honeywell 7400 (since Houston204 mentioned it and it was at Lowes) and connected leads as I had them in the old York stat. Set everything up (connected B to stat's C as directed, set 170 for heat pump, etc.), and it will not run the system at all. I can't even get the fan to turn on. I've tried setting it to single stage heat pump and everything else I can imagine. I went back to the original York, and it works fine and cycles. I don't know what could be the problem. Again, I just have R, W, G, Y, O, and B. Do I try another thermostat, go to the Hunter, or quit and go back to the nonprogrammable/mercury-tube old York.
Beyond the problem with the Honeywell, I don't understand the need for a multi-stage stat. I don't have anything like E, X, W2, W3, Y2, Y3, etc.
Cheers
Fred
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| | Houston204
| "Re(4):Wiring for Thermostat with Heat Pump" , posted Sun 19 Oct 20:03
I agree with Bama. You need a multistage heatpump stat.
The Honeywell RTH7400 is a good choice.
"Tip of the Day" Remember to remove power first.
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