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  #1  
Old 12/8/12, 9:28 AM
Gary Heller's Avatar
Gary Heller Gary Heller is offline
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Default heat pump cycling before reaching set point

Our new house has a Goodman 4 ton hp. We leave the unit off at night and house temp gets down to around 65 degrees and the outside temp is about 30 degrees. When we wake up I turn the unit on with a 70 degree set point. The unit will cycle several times prior to reaching an inside temp of 70 degrees. I've told the builder that this unit needs to be "trimmed". He disagrees. Should I be worried about "slugging" the compressor?



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  #2  
Old 12/8/12, 9:45 AM
Charley L. Bottger's Avatar
Charley L. Bottger Charley L. Bottger is offline
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Default Re: heat pump cycling before reaching set point

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Originally Posted by gheller View Post
Our new house has a Goodman 4 ton hp. We leave the unit off at night and house temp gets down to around 65 degrees and the outside temp is about 30 degrees. When we wake up I turn the unit on with a 70 degree set point. The unit will cycle several times prior to reaching an inside temp of 70 degrees. I've told the builder that this unit needs to be "trimmed". He disagrees. Should I be worried about "slugging" the compressor?
Not to worry about slugging the compressor, they are designed to operate in cold weather.

What do you mean cycle several times meaning into defrost or cycling off period before set point



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  #3  
Old 12/8/12, 9:56 AM
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Gary Heller Gary Heller is offline
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Default Re: heat pump cycling before reaching set point

It will run about 10 minutes and cycle off. Then it comes back on for 10 or 15 minutes and cycles off again. At a 30 degree outside air temp I don't think it should go into a defrost mode that quickly.



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  #4  
Old 12/8/12, 10:51 AM
Charley L. Bottger's Avatar
Charley L. Bottger Charley L. Bottger is offline
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Default Re: heat pump cycling before reaching set point

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Originally Posted by gheller View Post
It will run about 10 minutes and cycle off. Then it comes back on for 10 or 15 minutes and cycles off again. At a 30 degree outside air temp I don't think it should go into a defrost mode that quickly.

You have a problem Call a tech and send the builder the bill, or at least call the installing contractor and bypass the builder most contractors in my area place a sticker on the unit with their phome # the unit should still have a warranty.



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  #5  
Old 12/8/12, 11:08 AM
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David A. Andersen David A. Andersen is offline
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Default Re: heat pump cycling before reaching set point

If the thermostat shuts down when the air temp at the thermostat has not reached set point; it is possibly the "anticipator" in the thermostat is not set right.

If the temperature reaches set point but falls quickly after shut down; the wall the thermostat may not be insulated and there is a bypass to the exterior.







Air stratification can occur and it is 100F at the ceiling and 40 at the floor. This will cause a short cycle.





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  #6  
Old 12/8/12, 3:01 PM
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Marcel Gratton, CMI Marcel Gratton, CMI is offline
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Default Re: heat pump cycling before reaching set point

Quote:
Originally Posted by gheller View Post
It will run about 10 minutes and cycle off. Then it comes back on for 10 or 15 minutes and cycles off again. At a 30 degree outside air temp I don't think it should go into a defrost mode that quickly.
Thermostats installed too close to register will cause that problem. I relocated mine away from the 50in. plasma.



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