6 Reasons Why Your Furnace Keeps Switching Off and How to Solve It

Your furnace keeps your you comfortable during the frigid winter months, so it’s annoying when something isn’t quite right. One common situation is a furnace that endlessly kicks on and shuts back off all the time. This issue is called short cycling. It stresses equipment and may lead to costly repairs or even premature breakdowns.

Short cycling can be caused by for varying reasons. Before you book furnace repair, consider the likely causes and how to take care of the problem.

1. Clogged Air Filter

The HVAC filter catches airborne dust, hair and other pollutants that could wreak havoc on furnace. If you don’t change the filter often enough, it can eventually be clogged and decrease the airflow. When this takes place, a safety feature turns off the furnace to stop overheating. Inspect the filter, and if it’s dirty, install a new one. From here on out, install a new filter every 30 to 90 days to keep your furnace from short cycling.

2. Clogged Air Vents

A dirty filter isn’t the only thing that can lower airflow and overheat your furnace. Walk around your house and be on the lookout for for unopened or blocked air vents. For recommended system balance and performance, keep all registers open, even in unoccupied rooms.

3. Dirty Blower Wheel

The furnace blower consists of blades that move air through the ductwork. If they are caked with dirt, the air won’t move correctly, leading to overheating and short cycling. Regularly changing the filter is the best way to avoid a dirty blower wheel. If the blades are already dirty, schedule furnace maintenance to have them cleaned.

4. Faulty Thermostat

Check your thermostat next. This is the core of your HVAC system and gives the furnace instructions on what to do. Make sure the thermostat is in heating mode and auto fan with the desired temperature shown on the screen. Try changing the batteries. Also, check whether the thermostat is in direct sunlight or near a heat source that could influence the temperature reading. If you use a smart thermostat, visit the manufacturer’s site for troubleshooting guides.

5. Dirty Flame Sensor

The flame sensor turns off the gas valve when no burner flame going. The sensor can’t sense the flame if it’s coated in soot, so the gas switches off sooner and the furnace turns off. Leave the work of cleaning a sooty flame sensor to a professional like TML Service Experts.

6. Oversized Furnace

When it involves HVAC equipment, oversized isn’t always better. A larger system adds warmth to your home too rapidly, leading to unpleasant temperature changes and short cycling. The only way to fix this problem is to do new furnace installation.

If you attempt the fixes we went over here to no avail, it’s time to contact the professionals at TML Service Experts. We’ll take a look at the situation, figure out the cause, and perform the necessary work. Our goal is to reintroduce indoor comfort, energy efficiency and dependable furnace performance for the remainder of the season. And our services are supported by a 100% Satisfaction Guarantee for a year.* For more info about furnace short cycling, or to schedule HVAC repair, reach us at 208-488-4892 right away!


*Not applicable to the Advantage Program. See your signed Advantage Program Agreement for full details and exclusions. 100% Satisfaction Guarantee is subject to certain restrictions and limitations as set forth in the applicable Terms and Conditions.

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