What Is Heater “Short Cycling”?

Your furnace cycles on and off to maintain the temperature in your home at a comfortable level. The thermostat controls the cycle. When the temperature drops below the set point, the furnace will come on and heat the home until the desired comfort level is reached. Short cycling is when the furnace comes on and then shuts off repeatedly over a short period. In addition to being highly inefficient, rapid on and off cycling can reduce the lifespan of your heating system as it places an extra strain on the starter and other components.

What Causes Heater Short Cycling?

A number of different problems can cause your furnace to act irregularly. A few troubleshooting steps may isolate the cause of this potentially serious problem.

  • Improper airflow can cause the thermostat to register temperatures incorrectly. Dirty air filters as well as blocked air vents and registers can cause poor airflow. Replace the air filters and ensure that furniture, draperies, and other objects are not blocking your vents and returns.
  • If the thermostat is improperly located, it can be affected by drafts from doors and windows or the difference between indoor and outdoor walls. The thermostat should be mounted on an interior wall in a commonly used room. Block the thermostat with a piece of cardboard to prevent drafts and determine if the problem stops.
  • A heating unit that is too large for space will cycle on and off continuously. A properly sized unit will run for an extended period on a cold day in order to generate enough BTUs to heat the space before shutting off. A service technician can help you with the calculations to determine the correct size unit for your home.
  • Your thermostat may need to be recalibrated or have a loose wire. The furnace may also be overheating. Safety switches will shut it off to prevent damage. The unit will then come back on to heat your house, repeating the cycle. This can be caused by issues such as a cracked heat exchanger or dirty coils. These problems require the assistance of a trained professional.

Getting Help in Gainesville, FL

If your furnace or other heating system continues to malfunction, contact Bounds Heating and Air. We will gladly set a time to come by and inspect your system. Our highly trained service technicians will diagnose the cause and recommend a solution. We are proud to offer a full line of heating and cooling services to residential customers and can complete many repairs the same day.