Troubleshooting a Short Cycling Furnace

Short cycling in a furnace is a problem characterized by short cycle running of the furnace. The furnace turns itself off prematurely before completing a single cycle and then turns itself back on again after a short period. If you have noticed this with your furnace, it might be time to seek expert advice on its repair. Most causes for this kind of a problem are fixable though. The following are major causes of short cycling and how to solve them.

Troubleshooting a Short Cycling Furnace

1. Overheating

Your furnace could be turning itself off as a self-protection mechanism. When it overheats, the hot air inside gets trapped and sends a signal to the furnace that causes it to shut down to avoid further damage. This is because the excessive heat can cause cracks on the heat exchanger. To solve this, remove the air filter and dust it as excessive dust could be causing the blockage. Secondly, schedule a furnace maintenance routine with your technician and have them check the heat exchanger and repair any cracks that could have occurred already. If the heater is severely damaged, it could require a replacement.

2. The issue could be the thermostat

In a twist of things, the problem with your furnace could be external. It could be due to a malfunctioning thermostat that signals the furnace that the right temperatures have been met, making it turn off and on prematurely. Always strive to check the thermostat calibrations and ensure that it is functioning normally.

Check the Thermostat Calibrations

3. An Oversized Furnace

The work of a furnace is to generate heat to a given set level to warm spaces. If a bigger furnace is set in a smaller area, it heats the room rapidly than usual and ends up overheating the room. Due to the excessive heat, the furnace may keep turning on and off as it seeks to regulate the temperature. To solve this, make sure that the furnace is not too big for the room. There are different sizes of furnaces that fit in different spaces. Strive to install the proportionate size of a furnace to your space to avoid this problem. To get the right fit of a furnace for your room, you can consult your vendor or engage the services of an experienced technician.

4. Clogged Air Filter

Air filters in the furnace are designed to facilitate air exchange inside the heat exchanger of the furnace. If they are blocked, they can cause the furnace to malfunction hence the short cycling problem. To solve this, remove the air filters and blow off any dust or debris that might be clogging it. Once that is done, return the air filter and check if the issue is solved. If you still experiencing trouble, it might be time to buy a new air filter as it could be damaged.

Remove the Air Filters


Most short cycling issues are fixable through a simple furnace maintenance routines or replacement of the faulty furnace parts. If you are experiencing short cycling at your home, try the above troubleshooting solutions or call an experts to diagnose the issue and in no time, the furnace should be restored to its normal functioning state.

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