What to do if your furnace will not stay lit

January 20, 2021


A common problem that furnaces have is that the burners won’t stay lit. The furnace will start but then turn itself back off after a few minutes when this problem occurs. There are a few things that cause this.

Malfunctioning Thermostat

Your furnace could be malfunctioning. It’s falsely telling your furnace that the desired temperature has been met. You can fix this by replacing it with a new thermostat. If this doesn’t solve the problem, you can return the thermostat and look for other problems.

Broken Thermocouple

Your furnace has a thermocouple called the heat sensor. Its job is to close the gas valve if the pilot light goes out. A broken one can randomly close the gas valve, which shuts down your furnace.

Rim Country Mechanical, Inc. of Show Low, AZ, can replace broken heat sensors and perform other furnace repairs. We’ve been helping customers since 1993.

Restricted Air Flow

If your furnace doesn’t get proper airflow, it can overheat and shut down. This often happens because the air filter is clogged and needs to be replaced. You should check the filter every month and replace it when it appears dirty.

Blower Motor Isn’t Running

Your furnace will shut itself down if the blower motor isn’t operating as it should. It does this to protect itself from overheating. The motor has either lost power or is broken. The blower motor belt could be worn out, or the fan relay is malfunctioning.

Bad Circuit Board

Your furnace has a circuit board that controls it. Many of them have a display that flashes a code showing what the problem is. You’ll need to hire a licensed technician to fix this problem.

Full Condensate Pan

Some high-efficiency furnaces have a condensate plan that collects condensate. If the pan is full, a sensor will detect it and shut down the furnace. Inspect the pan and make sure the drain isn’t clogged.

Rim Country Mechanical, Inc. repairs, replaces and maintains furnaces and air conditioners. We also offer solar and indoor air quality services. Get in touch with us today to find out more.