4 Likely Culprits Behind Furnace Short Cycling

Posted on: 7 September 2022


At the first sign of your furnace turning on and off with unusual frequency, seek prompt, professional heating repair. If it's not addressed in time, this issue can cause wear and tear or complete failure to some furnace parts. Your furnace will likely short cycle if there are calibration issues with your thermostat or the air filter restricts proper airflow. Keep reading to learn more about the underlying causes of this problem.

You Have A Too-Large Furnace

When your furnace is too large to cool your home efficiently, it constantly turns on and off. This is because it releases heat too quickly and in an uneven distribution, which causes short cycling. Additionally, the faster heating cycle puts a lot of stress on your furnace components, causing them to break down. You're also likely to notice a spike in your energy bill due to the added strain. A viable solution to this issue is for your heating expert to recommend a suitably sized furnace for your home and perform a replacement.

Your Thermostat Is Faulty

If there's an issue with your thermostat, it will likely give the furnace incorrect readings. If this happens, your heater may receive confusing signals, causing it to turn on and off unexpectedly. Thus, contacting your technician for a resolution is crucial if your thermostat doesn't respond properly to commands. In cases where the display goes out periodically, check whether the batteries might be dying. If changing the batteries doesn't solve the problem, a technician can perform an inspection and advise on whether it's due to a wiring issue.

The Flame Sensor Is Malfunctioning

Without appropriate maintenance, the flame sensor can fill with dirt, which causes the flame to go out shortly after it's lit. Notably, if the sensor fails to detect a flame, it disconnects the gas valve, turning off the furnace. Still, the flame sensor can become corroded due to the moisture that the furnace creates during its operation. Over time, this moisture can cause rust in your furnace, which ultimately causes it to short cycle.

The Air Filters are Clogged

To effectively operate your furnace, check the air filter's condition regularly. If there are any clogs, they may compromise the flow of heated air around your home. Eventually, the furnace has to work harder than usual, causing it to short cycle. To resolve this issue, your filter should be replaced every few months.

Having a furnace that turns on and off frequently can be frustrating, especially if this happens when you need its services most. Even so, if your appliance exhibits this problem, enlist a heating contractor to diagnose it and determine the cause before fixing it.