4 Reasons Why Your Furnace Keeps Shutting Off

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February 20, 2023

Having a furnace during the cold winter season is a must to keep you and your family healthy and happy. When your furnace runs normally, it should kick on and off a few times every hour. However, if you've noticed that your heating system seems to be shutting off more often, it could be due to a number of issues.

4 Reasons Why Your Furnace Keeps Shutting Off

Clogged Air Filter

The most common reason your furnace is shutting off is that your air filter is clogged. As your air filter does its job, it will start to fill up with debris and reach the end of its usable lifespan. When this happens, your furnace will have difficulty forcing air through it quickly. This will cause your heating system to overheat and trigger its high-limit safety switch. Installing a new filter should remedy this problem quickly.

Dirty Flame Sensor

Inside your gas furnace, you'll find a safety device known as the flame sensor. Whenever it senses a flame present, it will allow gas to flow into your furnace. However, if it doesn't sense a flame, it will turn off the gas in your furnace to prevent unwanted gas buildup in the air. Unfortunately, while a flame sensor can be a great safety device, it can also get covered with soot and corrosion. This can make it malfunction and not sense that a flame is present. Simply cleaning the flame sensor should remedy this problem.

Oversized Furnace

While the phrase bigger is better usually applies to most things, it doesn't work for furnaces. If your furnace is oversized for your home, it will not be able to go through its heating cycle entirely and will shut off prematurely. This is not only annoying to hear, but it will create excessive wear and tear on your system and waste energy. It's best to have a furnace of the appropriate size installed in your home.

Improper Thermostat Placement

Your thermostat is the brain behind your entire furnace. It tells your furnace when it should turn on because your home is too cold and when it should shut off because it has reached your desired temperature. However, if you place your thermostat in the wrong location, it could be registering that your home is warmer than it actually is and shut your furnace off too quickly. Some improper locations include near a window with direct sunlight coming in, high up toward the ceiling where heat rises, or near a stove or register producing heat.

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