10 Reasons Why Your Heater Fails to Turn Off

October 20, 2021
Heater Troubleshooting in Roseville, MI

During the cold months, you might need to use your heating system for a more extended period. This doesn’t mean that the unit should run continuously. If your heater fails to turn off even after reaching the set temperature, it means that there is an underlying problem that needs attention.

A furnace that won’t turn off results in high utility bills and damage to vital components. It also creates unbearable indoor conditions. Here are some of the reasons why your heater could be running continuously and how to solve them.

1. The Thermostat Could Be Faulty

If your heater won’t turn off, the first thing you do is check the thermostat. The thermostat controls how the heating system runs. It detects the indoor temperature and signals the furnace to start or stop. So, if the thermostat malfunctions, it can signal the unit to run continuously. First, check the settings. If someone changes the fan setting to “on,” for instance, the blower will run continuously at any temperature. You can resolve this by changing the setting to “auto” so that the blower only runs when the furnace is running.

A heater working hard to maintain high temperatures can run continuously, especially when it’s frigid outside. So, when your heater fails to shut off, try turning the temperature settings lower. Give it a few minutes and observe how it works.

2. The Heating Unit’s Primary Controller Could Be Damaged

Heating systems contain primary controls that respond to the thermostat and control the unit’s start-up and run cycle. If the primary controller gets damaged, your heating system might not turn off. In such a case, you need to call a professional to diagnose and fix the issue.

3. You Have a Defective Check Valve

A faulty check valve can cause the heater to run continuously for those using a boiler heating system. If you have a defective check valve, the water circulates without regulation, which keeps the heating system turned on. Call a professional to replace the check valve to resolve this issue.

4. You Have a Clogged Air Filter

The air filters play a vital role in the heating process. They capture dust particles, pollen, pet dander, and other contaminants from your indoor air and keep them from getting to the heat exchanger. When neglected, such debris can accumulate in the air filter. A clogged air filter dramatically reduces the airflow throughout the heating system.

As a result, the heater won’t be able to circulate enough heat through your house. It will keep running in an attempt to maintain the set temperature. To avoid such issues, change the air filters after every three months. If you have pets or live in a highly dusty area, change the air filters more often, preferably monthly. For reusable filter models, clean them frequently. A unit with a clean air filter works optimally, and you should notice a significant difference in the airflow volume.

5. A Damaged Blower Motor

The blower motor’s main function is to circulate warm air from the heater into all the rooms in your house. If the blower malfunctions and fails to circulate warm air into the home, the thermostat will signal the unit to continue running. The main indication that you could be dealing with a faulty blower is when your heater is still running but you don’t feel any warm air coming out.

You should never attempt to repair the blower motor on your own. It contains some mechanical and electrical components that require extensive knowledge and skills to handle. In case you spot a problem with the blower motor, contact an HVAC professional immediately. They can diagnose the exact cause of the problem and recommend the most viable solution.

6. You Have a Leaky Ductwork

Damaged or leaky ducts allow the heated air to seep out. This causes the heater to run longer than it should. If your heater won’t shut off and you also notice uneven temperatures in different rooms in your house, you could have leaky ducts. Walk around and inspect the visible part of the ductwork for holes and gaps and seal them. If you are unsure of the exact location of the leak, have a technician inspect the ductwork and seal the leaks for you.

7. Poor Insulation

Heat always flows from hot to cold areas. If there are gaps in your house, the warm air will escape, so your heating system will have to run for an extended period to compensate for the lost heat. Insulate your windows, doors, floors, and walls to prevent heat transfer out of your home and lower the strain on your heater. Remember to also insulate the ductwork passing through uninsulated areas like the attic, crawlspace, and basement.

8. Your Heating System Is the Wrong Size

If you install an undersized heating system, it won’t keep up with your home’s heating requirements. As a result, it will run continuously in an attempt to increase your indoor temperature. On the other hand, if you have a heater that is too large, it heats your house super quickly then shuts off before the heat travels throughout the house evenly. It will thus keep turning on and off after a short period. If your heater won’t shut off, it’s probably the wrong size. Consult a professional to help you with correct heating system sizing based on the size of your house, its insulation level, your local climate, window location, and the number of occupants.

9. Your Heater Is Getting Too Old

With age, your heating system loses its capacity to cool your house adequately. Various components begin to wear and become inefficient. The heating system will thus need to run longer than it used to keep the home sufficiently warm. If your old heater won’t shut off, it’s time to consider upgrading to a new and more efficient unit.

10. Blocked Air Vents

Blocked air vents can significantly affect how your heater functions. The obstructions diminish airflow, so the system may not heat your house adequately, and it will thus run longer. Walk around the house and ensure that you keep off furniture and other objects away from the vents. Keep the grills clean and dust-free to maintain proper airflow.

Seek Professional Help If Your Heater Fails to Turn Off

If your heater still won’t turn off after trying out all the above solutions, it’s time to call a professional. Sometimes, it could be due to a fault in the control board or wires connecting to the thermostat. Only an experienced technician should handle such issues. You can avoid most heater problems by planning for regular heating system maintenance. During tune-ups, your technician will clean the components, lubricate moving parts, tighten loose electrical connections, and inspect the heat exchanger. This way, your unit will run at peak efficiency for years to come.

Whenever you need help with your heater, reach out to C & C Heating & Air Conditioning. We provide a full range of heating and cooling services. Our company also offers duct cleaning, water heaters, air filtration systems, and UV light services in Roseville, MI, and the surrounding areas. Reach out to us now and request our services.

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