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If your furnace turns off and on repeatedly, your first response probably is to panic. While this may be unusual for you, it is a prevalent issue that most homeowners in Toronto experience. Even if it’s pretty typical, it does not mean that you can merely ignore this concern when it happens. 

As the experts call it, short cycling involves constant power on and off of your furnace in an unusual manner. If not checked and corrected immediately upon happening, it could lead to expensive repairs and higher power bills. This extensive guide will discuss the possible culprits behind your furnace turning on and off constantly. If you are experiencing this, place a call to your trusted technician to troubleshoot the issue immediately.

You have an oversized furnace.

Proper furnace sizing is vital to having an efficient heating system. If you have an incorrectly sized unit, it could be a factor why your furnace turns off and on repeatedly. 

An average space with a large, overwhelming furnace would be a good example. If you have an oversized furnace, its heating capability could trigger a constant on and off power cycle. Why? Since larger furnaces deliver heat at a greater capacity than smaller ones, they disperse warmth faster than the latter. For this reason, larger spaces intend to use them. Once heat dispersion happens too quickly in a small area, the thermostat detects that the heating system has reached the desired temperature. It then triggers the system to power off. As the cold starts to creep in, it initiates the system to run again, which could happen in very short intervals. 

You have a problematic thermostat.

As mentioned above, the thermostat detects if the home’s temperature is within your standard preference. A defective thermostat could be behind why your furnace turns off and on repeatedly.

If your temperature reaches below or above the limit you set, your thermostat is the primary component that acts to balance it. A drop in temperature will trigger the furnace to function, while a higher temperature would stop the heating system’s operation. Once the thermostat, your indoor temperature detector becomes faulty, it might lead to constant power on and off. It could be a problem with its wirings, location, or batteries. You must check these factors as they may be contributing to the false detection of temperature that triggers anomalies in the system. 

Your airflow is restricted.

Insufficient or obstructed airflow could be why your furnace turns off and on repeatedly. While there is no one reason for this, it might be due to multiple issues that require immediate attention.

The first factor is a dirty air filter. When your air filters have clogs of dirt and debris, it tends to block the entry and passageway of the air. If you haven’t changed or cleaned your filters in a while, this could be a potential culprit. Next is a blockage within the supply vents. Air vents that are closed or have pieces of furniture blocking the entryway could trigger a constant power on and off. Once your heat exchanger receives insufficient air, it won’t transfer the adequate warmth that you need. Heat then builds up and results in short cycles.

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