Why Is Your Furnace Constantly Turning On and Off?

1 February 2021
 Categories: , Blog

Short cycling is one of the more common issues that you may experience with your home heating system. Short cycling occurs when your furnace turns on and off more often than it should. This type of constant cycling can prevent your home from warming up properly and could cause some significant damage to the heating system itself. If it is not corrected, you may see a rise in your energy bills and result in expensive repairs. Keep reading to learn why your furnace may be in this constant cycle of short cycling and what can be done.

Insufficient Airflow

One cause of short cycling is inadequate airflow. Several things can cause insufficient airflow. For instance, one of the most common reasons for low airflow is a dirty air filter. When a filter becomes dirty, there can be an excessive amount of heat in the exchanger, resulting in it overheating and shutting off. The filter should be changed at a minimum of every three months, possibly more frequently if there are pets in the home.

Insufficient airflow can also be caused as a result of blocked register vents. Therefore, go through the home and make sure they are all open and unblocked by rugs, furniture, etc.

Faulty Thermostat 

Another reason your furnace may be short cycling is due to the thermostat. The thermostat is responsible for controlling the furnace, and if it malfunctions, it could alert the furnace that the desired temperature for the home has been met, resulting in the furnace switching off. Your thermostat may have malfunctioned for many reasons, including bad batteries, faulty wiring, or its location in the home.

Oversized Furnace

If you have a furnace that is too large for the home, there is a good chance that it will go into a state of short cycling. The reason for this is because the over-sized furnace will heat the space too rapidly and then shut off abruptly. As soon as the temperature drops, the cycle will repeat quickly. Other than replacing the furnace with one that is sized properly for your home, you could use an advanced thermostat to lower the cycles per hour.

While the aforementioned are the primary reasons your furnace is short cycling, there could be other reasons. For instance, a corroded flame sensor, faulty fan limit switch, or inadequately designed ducting system could be to blame. If these are the problems, you will need to contact a professional for assistance. If you notice that your furnace is short cycling, contact a heating repair service near you.