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airheatman
airheatman, HVAC Technician
Category: HVAC
Satisfied Customers: 8380
Experience:  Furnace, A/C and heat pump specialist.
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I have a Honeywell VisionPRO TH8000 Series thermostat, running

Customer Question

I have a Honeywell VisionPRO TH8000 Series thermostat, running a Goodman heat pump/emergency heat unit, providing air conditioning and/or heating for our house.

Recently (April 2012), no matter what temperature or system (AC, heat, fan cycle, ON or OFF, etc.) I set the thermostat at - the fan keeps running and the house temperature is always at 78F.

The interior house temperature went to 88F when we were on vacation, even though I had set the thermostat to heat to 60F for the winter. I HAVE HAD TO TURN OFF ALL POWER TO THE AC/HEATING SYSTEM.
Please tell me how I can correct this situation!
Submitted: 5 years ago.
Category: HVAC
Expert:  M Oglesby replied 5 years ago.

M Oglesby :

YOu need to have your system checked.

M Oglesby :

It sound like it is low on freon.

M Oglesby :

Which means you have a freon leak.

JACUSTOMER-2hjzdrkd- :

Thank you. But WHY does the Honeywell house thermostat keep the interior temperature always at 78F? I have set it at 60F, but there is always a little bit of heat coming out of the registers, and in the basement, the return air ducts are cool, and the delivery ducts are warm. The heat pump runs (it is approx. 50F here in Montreal),but I cannot tell if the EM coils are also heating. Thank you, from Brian

JACUSTOMER-2hjzdrkd- :

Awaiting reply to request for clarification. Thank you, Brian

M Oglesby :

Are you saying the the set temp on the thermostat jumps to 78?

M Oglesby :

After you have set it to 60?

JACUSTOMER-2hjzdrkd- :

Brian replies:

JACUSTOMER-2hjzdrkd- :

No, I am saying that I cannot reduce the house temperature from 78F, whether I set the thermostat to 60F (heat mode or AC mode). Warm air is always coming out of the ducts. The heating part of the furnace appears to have a life of its own, since the thermostat appears unable to control it. NOTE: After the electricity being turned off all night, I have just turned the system on again; the heat (at a low temperature) is still being delivered, even with the interior temperature at 69F, and with the Honeywell thermostat set to "heat" to 50F only. I predict the heat will continue rising, very likely to 78F. I note also that the heat pump is NOT working, which means that the auxiliary heating system is on. In brief: the Honeywell thermostat is not functioning as it should. Note: the house and HVAC systems are relatively new, built in 2008. No service technician has been here since 2010. This excessive heating syndrome occurred while we were on vacation. Thank you.

JACUSTOMER-2hjzdrkd- :

Waiting for reply from M. Oglesby. NOTE: "Set" temperature does not "jump". Heat is still rising (1:52 pm est), no matter what the thermostat is set at. Brian

Expert:  airheatman replied 5 years ago.

Hello. My name is Tim.I will do my best to answer your question.Remember, you are not charged and I am not paid until you accept my answer.

Your problem is very possibly a heat sequencer stuck.

This allows the backup elements to stay on regardless of what the thermostat is calling for.I would start there.