Why Does My Furnace Keep Shutting Off?

Does your furnace keep shutting off? If yes, then it is a severe problem and can lead to significant issues such as permanent/irreversible damage if left unattended. When a furnace keeps shutting on and off frequently, it is called short cycling.

Let us take a look at some common causes of furnace short cycling.

Low Airflow

Low airflow is the number one cause of furnace short cycling. Some issues that can cause low airflow are:

Dirty filters: Over time, furnace filters accumulate dirt and dust and become clogged. A clogged filter can force the system to overdrive, eventually causing it to overheat and shut off. To prevent airflow issues, change furnace filters every 30-90 days.

Closed or blocked air vents: Check your vents for any blockage. If a piece of furniture is blocking a vent, relocate it. Remember, if your heat exchanger does not get enough fresh air, it can’t transfer enough heat, causing the system to short cycle.

Unclean blower wheel: Check your blower wheel’s blades to see if they are dirty. To prevent dirt from accumulating on the blades, change your filters regularly.

Dirty Flame Sensor

A dirty or corroded flame sensor can cause your system to shut down. To clean a dirty flame sensor, first shut off the power to your furnace (locate and press the light switch or turn off the breaker for your furnace).

The flame sensor is usually mounted by a ¼” hex head screw. When you remove this screw, the sensor will slide out. Carefully remove the sensor. To clean your flame sensor, gently rub it with light grit sandpaper. Then wipe it with a clean paper towel to remove accumulated dirt.

Once you have cleaned the sensor, reconnect the wire and remount the sensor on the burner assembly. Replace the door and turn the power back on.

If your flame sensor is broken, replace it.

Faulty Thermostat

Check your thermostat’s wiring to see if it is frayed. If the wiring is too old, consider replacing it. Do not place your thermostat near a heat source or in an area that receives direct sunlight. Check the batteries and replace them if necessary.

Is your furnace not heating properly? Let Countryside Heating & Cooling Solutions help. We offer top-notch furnace repair services in Bryant. Our seasoned technicians know everything there is to know about heating and cooling systems. We will treat the root cause of your heating or cooling problem, not just the symptoms. To schedule an inspection, call 763-299-9996.