Coil continues to Heat past therm setting


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Old 12-11-06, 10:20 AM
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Coil continues to Heat past therm setting

Hello,

I have a westinghouse HP electric Heat/AC system, and a White-Rogers Thermostat. Recently, my thermostat records the proper room temperature setting but when when I set a target room temperature, heating continue upward right on past that temperature, until I turn the system off.

I have determined that the HP blower properly turns off when the target setting is encountered but the heat continues to come from the in-house vents. Therefore, I assume the electric furnace is running past the setting for room temperature.

I have my thermostat set for heat pump usage, not furnace only.
From a lay perspective it would appear I have a thermostat problem, but it is digital, and that it would just up an quit this way is surprising. The entire system is only about three years old.

Thanks in advance for any input.
 
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Old 12-11-06, 11:25 AM
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Out of the box here. When you push up the tstat that did turn on the electric furnace also. With the sequencers for the electric heat. Can be that they stick on on you there and not in the tstat. Check them out when you have that heat and no blower
 
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Old 12-11-06, 01:21 PM
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Originally Posted by Ed Imeduc View Post
Out of the box here. When you push up the tstat that did turn on the electric furnace also. With the sequencers for the electric heat. Can be that they stick on on you there and not in the tstat. Check them out when you have that heat and no blower
Thank you for your reply. i know nothing about electric heat systems. I assume the indoor "furnace" is supplemental and normally does not always run in conjunction with the heat pump. The sequencers you speak of would determine when the indoor heat turns on and mine might be stuck. Where are these sequencers and how can I test them?

Thanks again
 
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Old 12-11-06, 02:33 PM
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The sequencers you speak of would determine when the indoor heat turns on and mine might be stuck. Where are these sequencers and how can I test them?

The electric heat turns on when the heatpump cant keep up with the home.Or when you push the tstat up a little.
The sequencers are in the furnace or blower coil unit.and you would have to use a meter to find out what is what
 
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Old 12-11-06, 04:08 PM
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The electric heat turns on when the heatpump cant keep up with the home.Or when you push the tstat up a little.
The sequencers are in the furnace or blower coil unit.and you would have to use a meter to find out what is what

Thanks again. I originally was hoping this was the thermostat as I think I could replace that. Your theory makes more sense as my experience is that digital circuitry doesn't often just up and stop working. I've researched sequencers a little for electric furnaces and don't think I have either the time or know-how to replace them. Assuming it is a stuck sequencer, (1) is this labor intensive for a knowledgeable repairman and (2) is the replacement part itself expensive?
 
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Old 12-11-06, 04:16 PM
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Cost are so different across the country that its hard to say cost for this job
 
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Old 12-11-06, 05:33 PM
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Stat could be bad.

If you are asking for a jump of more than 2 or 3 degrees, you are probably causing the thermostat to turn on both the heat pump and the electric strips, a two stage system. If you don't change the stat setting, will it hold the temp and work properly?? Try only raising the setting by 2 degrees and see what happens.
If that works then the problem really could be the digital thermostat. Since you can turn the heat off from the stat when it goes past the set point that would indicate to me that the contactor relay for the heat strips is not stuck. The air handler blower should run after the strip is turned off long enough for the strip to cool down and it normally would continue to run after the hp takes over. If you try another stat be sure it is for a 2 stage hp since that appears to be what you have. Just thinking out loud but, Should be 3 ways to turn the heat strips. 1 would be for the heat pump sequencer to ask for electric heat. 2 would be for you to tell the stat you need a large temp jump and it turns on both. But then the stat should turn off the elect strip maybe 1 degree before you reach the set point and then at the set point the stat would turn off the hp. 3 would be the emg heat mode where only elect strips are used for heat.
 
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Old 12-11-06, 08:49 PM
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f you are asking for a jump of more than 2 or 3 degrees, you are probably causing the thermostat to turn on both the heat pump and the electric strips, a two stage system. If you don't change the stat setting, will it hold the temp and work properly?? Try only raising the setting by 2 degrees and see what happens...

Thank you for your suggestions:
I set the thermostat up two degrees above room temperature and heat on. Normally the HP fan starts but now it doesn't, but I can feel air coming from the furnace blower. The temperature here has been in the mid 50's today so I wouldn't think the HP needs any help. Right now my room temperature is 78, the stat is set to 76 and the furnace blower is on. Last night I had to set the thermostat off because otherwise the temperature just keeps going up.

If it helps to know, the HP fan will start start when I set the thermostat to a temperature lower than the room temperature and turn on AC at the stat.
 
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Old 12-12-06, 08:18 AM
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If it helps to know, the HP fan will start start when I set the thermostat to a temperature lower than the room temperature and turn on AC at the stat.

Id say it should do that

I set the thermostat up two degrees above room temperature and heat on. Normally the HP fan starts but now it doesn't, but I can feel air coming from the furnace blower.
Im back to the sequencers can be it,heat speed on the blower????
Ill add this . Last summer we had 3 service call for high electric bills on AC units. Dont know why or how but it was a sequencer on the units that had a element on. On all of them
 
 

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