Why Do I Hear My Furnace Turning on and Off?

Hummmmmmmmm…Why is your furnace making the noises that it does? May be time for a tune-up!







Do these sounds seem familiar? In most Triad houses during the winter, you can hear these sounds regularly as the furnace cycles on and off, keeping the house at a comfortable temperature. If you have your heat set at 68, for instance, the thermostat will tell the furnace to cycle on as soon as the temperature drops to 67. Once the furnace brings the temperature back up to 68, however, the thermostat tells the furnace to turn back off.

When working properly, a furnace cycles on three to six times per hour. However, when it short-cycles, it turns on and off every five minutes or more. This can indicate a serious problem with your furnace, and you should investigate right away. Here are some of the common reasons why furnaces short-cycle, some steps you can take at home, and some tips on when to call in the experts at Johns Plumbing, Heating, and Air Conditioning, Inc.

Short-Cycle Reason #1: Dirty Filters

If you don’t change your air filter frequently enough, it can collect dirt and debris. This reduces airflow, which can result in mixed messages between the furnace and thermostat. Fortunately, this common problem is one of the easiest to fix; simply replace the filter, turn the heat back on, and see if the short-cycling stops.

Short-Cycle Reason #2: Thermostat Problems

Since the heating cycle relies on communication between the thermostat and the furnace, it makes sense to make sure that the thermostat is not the problem. Start by checking the thermostat battery; again, this is a quick, easy, and cheap fix if this is the problem. Also, check the location of the thermostat; if it’s too near a heat vent or a fireplace, it might be turning off too quickly when the hot air blows on it.

Short-Cycle Reason #3: Furnace Problems

If your furnace it too big for the space it’s meant to be heating, it can cycle on and off too frequently, trying to find the right temperature. This is a common problem that Johns can solve by adjusting the furnace down to the appropriate heat output. Another potential culprit is the pilot; make sure that it’s lit and working properly.

If you can’t stop your furnace short-cycling with any of these tips, make sure to call Johns Plumbing, Heating, and Air Conditioning, Inc., today to schedule an appointment. Short- cycling can drastically reduce heating efficiency and shorten the life of your furnace.

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