tstat wiring


  #1  
Old 01-26-13, 11:12 AM
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tstat wiring

I'm not going to hijack the other thread, but here's a photo of the thermostat wiring. Unlike the other poster, there is no W2 screw. There is a jumper from a terminal called "U" to W, but that's it. Wondering if this is wired right. Stays on Aux heat at all times. That's why his electric bill was $390 for two months. Possible a coolant check is in order? Unit is running outside and putting out cold air at fan, unlike warm in summer. I know that ain't squat, but it's information.

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  #2  
Old 01-26-13, 11:19 AM
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If the HP is running and the aux is running, that is normal, but the HP would not be putting out the correct capacity if it low on refrigerant.

X2 is emergency heat and W is aux on your thermostat.
 
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Old 01-26-13, 11:24 AM
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If it is all wired right, I'll just have him call out someone to check the charge in the unit. The tstat is set at 50 and the house is 50, so you are saying AuX heat should be on? I always thought AUX heat was to supplement the HP, say if the house was 50 and you jammed it to 65 or 70. Otherwise, I thought AUX stayed off and the HP did the work.
 
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Old 01-26-13, 11:50 AM
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yes, chandler you are correct about the operation, but just because that old thermostat says that it is 50 and just because it is set a 50 does not mean that either are accurate. Those old mercury thermostats get out of wack easily. If you turn down the thermostat, slowly, does the aux shut off and only the HP run? Is the thermostat in emergency heat instead of heat?
 
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Old 01-26-13, 12:42 PM
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Kevin, the tstat has a direct switch for Emergency Heat and it is off. I have the tstat set at 50 and the house feels 50 (where the thermometer says). Aux won't turn off at all, and it comes on immediately. If I put a more modern tstat, will it have reference instructions as to what needs to be done with the wiring, like jumpers, etc? I don't paint and I don't do HVAC. Just trying to help out a yankee in Ft Lauderdale, 800 miles away
 
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Old 01-26-13, 12:44 PM
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If you remove X2 and W wires does the aux heat shut off?
 
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Old 01-26-13, 01:16 PM
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I'll go back by there and try that. Let you know. Thanks again.
 
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Old 02-05-13, 05:26 AM
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Had my local HVAC guy check it out. He confirmed what you said, that the antique tstat had to go, and installed a new one. However, the owner, in WPB, FL, is monitoring his daily usage, and it only dropped from, I believe, 73KWH to 69 KWH after the install. I went back over today and the house was 49, while the tstat was set on 45. I pumped the tstat to 51 just to be over ambient. HP came on and about 2 min later the AUX came on.

Called the HVAC guy and he is coming out Wed to set the tstat from "comfort" to "economy", whatever that means, so maybe it will correct itself. Not occupied in winter, only refrigerator, HP and security system are using power, so his high bill, IMO, is not warranted for such a small place. My bill is 1/3 his, and we live in it with everything running.

Thanks for the comments, and I'll post a followup.
 
 

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