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View Full Version : Heat pump thermostat won't turn off


rick73852
Mar 15, 2014, 12:55 PM
I have a Trane heat pump controlled by a Honeywell thermostat (model #TH3210D104).

I am having a problem with the heat pump warming the house to the normal setpoint for comfort (say, 70 or 71) during the day but the heat pump continuing to run. By continuing to run, I mean the whole system, inside and outside units (fan, compressor unit).

Today, we are having temps in the mid- to upper-60s. I had I lowered the setpoint to 50 and the unit would turn itself off. However, if I raise the setpoint, the problem with it continuing to run recurs.

On especially cold nights (in the 30s or even into the high 20s), the heat pump will run for hours without cutting off and it doesn't appear that the auxiliary heat ever comes on.

I called an HVAC service to come out several times and the tech looked things over. He said the refrigerant level, compressor, defroster, heat strips, etc. all seemed fine. He has replaced the thermostat three times. Finally telling me that he thermostat location must be the problem. I moved the thermostat and it did not clear the problem.


Today's example, as I type: I had the setpoint at 66 since this morning. While reading over this site, I reset the thermostat to 69. The unit has raised the temp to 69, but now the heat pump is continuing to run and there is no sign of the auxiliary heat coming on, although the setpoint of 69 was reached 15 minutes or so ago.

It sounds reasonable to me that this may be a thermostat issue, but I wanted to see if I could find any other information/assistance that might help confirm that diagnosis before I purchase a new thermostat.

I've spend about $800.00 so far on service calls and thermostats so far with the same problem. Anyone have any ideas?

Same problem during cooling season with it not shutting down when reaching setpoint.



Thanks!
Rick