jtfussell

I have a carrier model 48ss. Last year, we had the burner replaced due to it having holes in it from being old, as well as the blower fan motor. Well this year, the system will turn on, the heat will kick on in the house, and then sometimes, it will cut off but the system will still be running. The only way to shut it off so that the $$$$$ isn't going out the roof is to cut it off at the breaker. Does anyone have any advise on this matter?

HeatPro

quote: "it will cut off but the system will still be running."

The IT is the problem. As the furnace is part of the system, IT cuts off, but we don't know what that is. Usually the heater continuing to run is due to a sticky relay or a shorted wire. Certainly, having no control of the burner is a severe problem that can burn the exchanger and suffocate you, so finding the particular IT is necessary. The safest course is to turn it off until someone who knows the electrical troubleshooting procedures for electrical furnace circuits can find and fix the reason the IT turns off, but not the flame.

riggs

I agree you have a serious and dangerous situation. It's really time to get another furnace. I would check the control board. Sometimes the soldered connections get loose from the heat or something gets burned up. Your limit switch by the exchanger is supposed to send a signal to the board to shut off the gas valve. Another possibility is bad valve (not as likely though) that won't shut off. So check the voltage there.

I would highly recommend retiring the unit. If there's a hole in the exchanger, you're going to suffocate like HeatPro said.