Aux. mode on Heat pump not satisfying tstat (Ducane)


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Old 12-21-04, 09:08 PM
jimbo122655
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Unhappy Aux. mode on Heat pump not satisfying tstat (Ducane)

My problem ocurred the past 2 nights when the temp. went down into the teens. The auxilary mode kicked on so i was running both heat pump and aux. but the tstat temp. went from 70 to 62 before I realized it and I had to switch it to emergency heat and run it there until it warmed up outside. I have had problems with this unit for the past year when I bought this new house. It is a 2 ton unit heating/cooling approx. 1400 square feet. I also have a gas furnace for the first level of my house, also 1400 square feet, and it seems to work fine. A month ago, I had the heat pump serviced because it was always freezing up outside even when the temp. was around 60. It was low on freon and they charged it. Now when it goes into the defrost mode, there is never any frost on the unit, it just goes through the motions with the whoosh and all. I set the defrost pin to 90 minutes which was previously set by the techs at 30 minutes. Could too much freon be causing my problem now? I have a feeling the unit is overcharged and I understand ,that being that, it is hard on the compressor. When I look down inside the outdoor unit, it appears to be clean and I always change the filters on my returns every month religiously. I am just puzzled why the aux heating doesn't satisfy the tstat setting. Thanks, Jim
 
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Old 12-21-04, 09:34 PM
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What is used for Aux heat? Gas or electric strip?
 
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Old 12-22-04, 06:55 AM
jimbo122655
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Electric strip. I also didn't mention that I went up into the attic to make sure the furnace was running when the thermostat had the aux. heat signal on and the furnace was in fact running. I live in Winchester, Virginia and for the most part, the temperature in this climate isn't too awfully cold. Last night, the temp. was about 32 degrees and the heat pump was able to maintain but I know that when it drops again, I'll be going to "emerg. heat" if I can't get this problem soved.
 

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Old 12-22-04, 08:22 AM
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What type of t-stat do you have, 2stage? single stage?

Have a remote sensor outside?
 
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Old 12-22-04, 01:04 PM
jimbo122655
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It's a 2 stage tstat. The service guys were just here and they said the outside unit took 4 ounces of freon. They were here 2 months ago and added a pound. If this is the case, then I must have a leak. The heat pump had a leak in the early spring (coils) which they repaired. The techs were trying to tell me that aux. heat and emerg. heat are the same thing in essence. Now I need another cold night and unfortunately not one in site to see if the aux. heat works with the heat pump to maintain the tstat setting of 70 degrees. They also tried to tell me that when it gets really cold outside, I should periodically switch to emergency heat to satisfy the tstat because it's hard on the heat pump. I thought that was what the aux. heat was for. I think they are feeding me a line. I still wonder too if the unit is suffice to heat and cool the second floor. 2 ton, 10 seer for 1400 square feet. I have 10 heat ducts and 4 returns running from this heat pump/furnace. Jim
 
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Old 12-22-04, 03:37 PM
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Aux and Emgerncy heat is the same thing.. Aux just kicks in when the temp drops at the stat, and also kicks in when it goes into defrost.

Emg heat take the heat pump off line, and just using the strip heater only.

I don't know where you are, some heat pump set up has a remote outdoor sensor.. WHen the temps drops below say, 32 degrees. it turns off hte outdoor unit and turns on the aux heater to keep the temp

WHen the temp gets so low, the heat pump can only pull soo much warmth out of the cold outside air.

2 tons sounds about right, at least for here in MN.

I'd be happy to send you -8 tonight from Minnesota! :-) It'll be my christmas gift for you!
 
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Old 12-22-04, 05:45 PM
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Talking

Thanks Jay, but no thanks......lol....I'll just stay here where it is 45 degrees right now, going down in the high 30's tonight. I just need a good night to retest this whole system. Jim
 
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Old 12-22-04, 06:07 PM
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Two stage tstat. Is it a 2 stage compressor???? Are did tehy mean that when it droped 2o that the AUX would kick in? 4 oz now a lb of freon then. Id get the guys back now and find the leak and fix it for sure. If not just forget the heat pump and stay on EMG heat. You can hurt the compressor
1400sq ft Dont know what the load is there But 2 ton with 10 outlets and 4 return Dont sound right . Dont know how old unit is but a 10 seer is very very low And what is the HSPF on the heat pump? They dont work off a outside tstat unless you have a oil are gas back up. Then when so cold the tstat will just turn over to the oil are gas.

ED
 
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Old 12-25-04, 02:10 PM
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I emailed a friend of mine who owns a HVAC company. He said that the problem sounded like it was in the tstat. I then pulled the cover off and sure enough found a prong that was bent down and not making contact. I am thinking now that that prong controlled my aux. heat. If this is the case, it makes sense that unit was calling for secondary heat and the aux. light would come on but no contact was being made to the furnace and that is why my temperature was dropping so fast. In essence, I was striclty heating with the heat pump and not heating with aux. heat even though the light was on making me think that it was working. Tonight will tell since the temp is going down again. Jim
 
 

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