Why Won't Your Heating System Shut Off?

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When you have a heating system not shutting off, this issue makes it difficult to maintain the desired temperature inside the home. Your furnace or heating unit is likely wasting energy, and this problem could raise your heating bills.

When you experience problems with the furnace inside your Indianapolis home, you can always give us a call at Williams Comfort Air. However, this particular heating issue is sometimes solvable without professional HVAC repair. Our technicians share the reasons why your furnace keeps running and doesn’t shut off, as well as what you can do to fix minor issues without calling for service. Year-round, trust our team of NATE-certified heating and air conditioning technicians to stop your HVAC problems and make your home more comfortable.

Why Your Heating Unit Keeps Running & Doesn’t Turn Off

When a furnace or heater continues to run and doesn’t stop when the room reaches your desired temperature, or it runs longer than expected, a few issues could be the problem.

1. Improper Thermostat Setting

If it is getting too hot in your home and your furnace is still running, the problem may be simpler than a broken system. Someone else in the home may turn the thermostat setting up without your knowledge, setting the heat well above your desired temperature. Make sure the thermostat is set properly before looking into more complex issues.

  1. Check the thermostat settings for the temperature. Make sure the thermostat is set according to your preferences and not too hot, as you may need to adjust the temperature down.
  2. Try to switch the temperature setting below the current room temperature – this should trigger your furnace or heater to turn off. See that it does cause the heating equipment to stop, then set the temperature properly according to your preferences.

2. Incorrect Fan Settings

Sometimes, the furnace or heater isn’t actually running, but it sounds as if it is because the blower fan continues to run. If this is the issue, you need to check the thermostat to make sure the correct fan setting is in use – you may need to switch it. It is likely that the fan has been set to run all the time, rather than only during a heat cycle. The blower fan is capable of running independently of the furnace or air conditioner, but you typically want to use the setting that only allows it to run with your HVAC unit to save energy and better control room temperature.

  1. Check your thermostat settings for the fan. Your thermostat may have a toggle switch to adjust the fan settings between ON and AUTO, or this setting may be adjusted on the display if you have a digital thermostat.
  2. Make sure the thermostat is set to the AUTO fan setting. This setting allows the blower fan to run only as the furnace heats. With the ON setting, the blower fan runs around the clock, and will blow cool air into your home when the heat is not on, which can disrupt the temperature and waste energy.

3. Dirty Filter

If you have a forced air furnace or heat pump and air handler, the system uses a filter to remove airborne dust and dirt, to keep these particles out of the unit interior. When the filter becomes too dirty, the amount of air moving into the furnace or heater is limited, which forces the unit to work longer to properly heat your home and it won’t stop when you may expect it to. To fix this problem, a new filter is needed.

  1. Remove the old filter from the filter compartment.
  2. Insert a new filter of the same dimensions into the filter compartment. Make sure the filter is positioned correctly according to the arrows on its frame.
  3. Dispose of the dirty filter and replace the filter compartment’s access panel, if applicable.

* If your system uses a washable filter, lay the filter flat with the dirty side up and use a vacuum to remove debris. Rinse the filter with water to remove any leftover particles. Allow the filter to fully dry before reinserting it into the unit.

4. Thermostat Malfunction

The job of your thermostat is to read the room temperature and communicate heating needs to the furnace or heating unit. If there is a problem with the thermostat, it may not communicate properly and make your furnace to endlessly run and heat the home. A loose wiring connection is one of the common causes of problems with thermostats, and you may need to tighten the wiring.

  1. Turn off power to your furnace or heater at the circuit breaker.
  2. Remove the thermostat cover to access its wiring panel.
  3. Check the thermostat wiring connections to see if any are loose. Tighten wiring connections with a screwdriver.
  4. Replace the thermostat cover and restore power to your heating unit.

It may be possible for a professional to fix the issue if you cannot, but thermostats may need to be replaced through repair services from your HVAC contractor. Occasionally, sensors will go bad or a switch will break.  In this case, you are due for a thermostat upgrade – your technician can help you select a unit that offers the energy efficiency and control you desire.

When You Need Repair

Some issues that cause a furnace or heat pump to continue running and fail to turn off cannot be corrected through simple troubleshooting. A faulty limit switch or compressor contact within the heat system can cause this issue, which require professional repair to fix the system properly. If you have tried each step above and your furnace is still running, it’s time to give us a call to schedule repair services.

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