Carrier thermostat - http://www.hvacmechanic.com/ Forums
Original message
| Satfred
 |  "Carrier thermostat and hp cycles off too soon"
, posted Wed 12 Dec 13:08:  
I have a Carrier TSTATCCPDF01-B thermostat that controls a 3 ton Carrier Performance Series Heat pump with a 80% gas furnace for backup heat. The lockout settings are 2 C and -1C respectively. When the temp is around 1 C and there is a call for heat, the heat pump starts and runs for exactly 15 minutes then the backup heat kicks in. I have read all the posts that this is probably a defrost cycle but it seems strange to me that it occurs 15 mins every time. I read the operating instructions for the thermostat and it states that "If the heat pump does not make a sufficient improvement within a reasonable time period (ie 15 minutes) then the gas furnace will come on to satisfy the indoor temperature demand" Is this what is happening? If so this doesn't seem too efficient. The heat pump seems to just start producing warm air and then cycles off.
Is there a way to adjust the amount of time the thermostat allows for the heat pump to satisfy the heat demand before having the gas furnace come on? The house is 3300 sq ft and the duct work only allowed for a 3 ton heat pump so there is some concern that the heat pump may be a little undersized.
I have thought about just changing the Balance point temp and Aux Heat lockout setting to the same temp. If so, what temperature would someone suggest?
Thanks in advance for any advice.
[this message was edited by Satfred on Wed 12 Dec 13:10] |
| Replies:
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| theduke03
| "Re(1):Carrier thermostat and hp cycles off to" , posted Wed 12 Dec 18:51
I dont see how a 3 ton heat pump could heat a 3300sq ft house unless your house is inside of a heated bubble! You can adjust those settings on the stat.
You can't put a price on comfort! Be Safe.
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| | Satfred
| "Re(2):Carrier thermostat and hp cycles off to" , posted Thu 13 Dec 13:18
Thanks for the reply.
The heat pump was added after the house was built. When the temperature is above 2C it does heat the house well. It's just when it gets colder the backup heat kicks in. When you say I can change the settings would it be best to make the lockout settings 2C so as not to bother having the heat pump cycle on and off. Looking at it from an efficiency (I'm told hp are still more efficient than a gas furnace at 0C or 32F) vs wear and tear stand point.
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