Looking for an advice about York HVAC package gas furnace and AC in one. It is around 20 years old and located in SC.
My furnace about once a month experiencing this thing: it is heating up to a set temperature, then burners shut off and the blower continue running to cool down the exchanger, and it can run indefinitely like stuck in this mode and not heating anymore.
One day I was at work and the blower ran for 9 hours and when I got home the room temp was so low with the blower on.
How I handle this is turning thermostat off, the blower is still running for about 5 minutes and then turns off, then I switch the thermostat back to heat and the furnace works normal cycles for another month.
Tried to replace a thermostat, no changes. There is no restricted airflow. Thermostat fan is set to AUTO mode. Filter is MERV 4 or 6, so not very thick.
I suspect it could be a limit switch stuck open and not let the furnace to complete the cycle preventing the burners to start up.
Can a limit switch stuck open about once a month? I also see this happening when outside temperature is very cold like 32 degrees. Is there anything else can cause this issue?
Appreciate for your help on this.
