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Rick, HVAC Supervisor
Category: HVAC
Satisfied Customers: 21386
Experience:  40+ yrs. experience as a licensed oil & gas technician.
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I have a Honeywell thermostat. It is showing a flame but the

Customer Question

I have a Honeywell thermostat. It is showing a flame but the heater is blowing cold air. What does that mean?
Submitted: 6 months ago.
Category: HVAC
Expert:  Rick replied 6 months ago.

Welcome to Just Answer, my name is ***** ***** I will do my best to help you with your issue. If my initial response doesn’t answer your question then let me know and we can continue our conversation.

It means the thermostat is calling for heat but there is a furnace malfunction. Usually an open limit circuit. This can be caused by a dirty filter among other things.

Customer: replied 6 months ago.
We had a HVAC technician look at it the other day and replaced the flame sensor. Do we need to replace the thermostat? Seems like sometimes it will heat and other times blows cold air.
Expert:  Rick replied 6 months ago.

This doesn't sound like a themrostat problem. If the filter is clean then about the only other thing you can try is resetting the rollout switch(es) (see attached pic for typical). They are located just outside the burner chamber. Turn off the power then press the small button between the 2 leads to reset it. If it clicks you have reset it and the unit will fire up when you turn the power back on with any luck. If it doesn't click it wasn't tripped.

Check to be sure there isn't more than one by tracing the leads connected to the switch. If that doesn't work then it's time to call in a pro.