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

Your furnace keeps your home cozy during the harsh winter months, so it’s disconcerting when something is off. One routine complaint is a furnace that continually switches on and shuts back off again. This problem is called short cycling. It stresses your heating system and might result in expensive repairs or even premature breakdowns.

Short cycling can be caused by for several reasons. Before you request furnace repair, consider the potential causes and how to fix the situation.

1. Clogged Air Filter

The HVAC filter attracts airborne dust, hair and other pollutants that could cause problems for furnace. If you don’t get a new filter regularly, it can eventually be filthy and decrease the airflow. When this happens, a safety feature turns off the furnace to avoid overheating. Inspect the filter, and if it’s dirty, get a new one. From here on out, replace the filter every 30 to 90 days to stop your furnace from short cycling.

2. Clogged Air Vents

A dirty filter isn’t the only trouble that can lower airflow and overheat your furnace. Walk around your house and be on the lookout for for shut or obstructed air vents. For adequate system balance and performance, keep all registers open, even in unused rooms.

3. Dirty Blower Wheel

The furnace blower has blades that distribute air through the ductwork. If they are dirty, the air won’t travel correctly, creating overheating and short cycling. Frequently replacing the filter is the best method to stop a dirty blower wheel. If the blades are already dirty, schedule furnace maintenance to have them cleaned.

4. Faulty Thermostat

Examine your thermostat next. This is the brain of your HVAC system and tells the furnace what to do. Make sure the thermostat is set to heating mode and auto fan with the desired temperature displayed on the screen. Try changing the batteries. Also, check whether the thermostat is in full sunlight or near a heat source that could impact the temperature reading. If you use a smart thermostat, check the manufacturer’s site for troubleshooting guides.

5. Sooty Flame Sensor

The flame sensor is responsible for turning off the gas valve when no burner flame going. The sensor can’t find the flame if it’s sooty, so the gas turns off prematurely and the furnace turns off. Leave the work of cleaning a dirty flame sensor to a professional like Service Experts Heating & Air Conditioning.

6. Oversized Furnace

When it involves home comfort equipment, oversized isn’t always better. An oversized system warms up your home too rapidly, leading to unpleasant temperature fluctuations and short cycling. The only way to fix this situation is to schedule new furnace installation.

If you try the fixes we covered here to no avail, it’s time to call in the pros at Service Experts Heating & Air Conditioning. We’ll take a look at the situation, diagnose the cause, and provide the necessary work. Our goal is to bring back indoor comfort, energy efficiency and reliable furnace performance for the rest of the season. And our work is supported by a 100% Satisfaction Guarantee for a year.* For more info about furnace short cycling, or to schedule HVAC repair, reach us at 239-908-6991 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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