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

Your furnace keeps your house warm during the frigid winter months, so it’s disconcerting when something is off. One frequent complaint is a furnace that continually turns on and turns off over and over. This issue is called short cycling. It stresses your furnace and may result in pricey repairs or even earlier than normal breakdowns. 

Short cycling can happen for a few reasons. Before you schedule furnace repair, research the possible causes and how to resolve the problem. 

1. Dirty Air Filter 

The HVAC filter catches airborne dust, hair and other substances that could wreak havoc on furnace. If you don’t replace the filter often enough, it can get dirty and decrease the airflow. When this occurs, a safety mechanism switches off the furnace to stop getting too hot. Inspect the filter, and if it’s dirty, replace it. Going forward, replace the filter every 30 to 90 days to keep your furnace from short cycling. 

2. Obstructed Air Vents 

A dirty filter isn’t the only issue that can lower airflow and overheat your furnace. Walk around your residence and look for shut or crowded air vents. For recommended system balance and performance, keep all registers open, even in unoccupied rooms. 

3. Dirty Blower Wheel 

The furnace blower has blades that distribute air through the ductwork. If they are caked with dirt, the air won’t move correctly, creating overheating and short cycling. Regularly replacing the filter is the simplest 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 tells the furnace what to do. Ensure the thermostat is on heating mode and auto fan with the desired temperature showing on the screen. Try putting in new batteries. Also, check whether the thermostat is in full sunlight or near a heat source that could affect the temperature reading. If you use a smart thermostat, go to the manufacturer’s site for troubleshooting guides. 

5. Soot-Covered Flame Sensor 

The flame sensor turns off the gas valve when no burner flame going. The sensor can’t detect the flame if it’s coated in soot, so the gas switches off sooner and the furnace shuts off. Leave the work of fixing a dirty flame sensor to an Expert like A-Plus. 

6. Oversized Furnace 

When it involves heating and cooling equipment, larger isn’t always best. A bigger system adds warmth to your home too fast, creating uncomfortable temperature changes and short cycling. The only way to resolve this problem is to request new furnace installation. 

If you try the fixes we mentioned here and nothing has changed, it’s time to contact the pros at A-Plus. We’ll review the situation, figure out the cause, and provide the necessary work. Our priority is to bring back indoor comfort, energy efficiency and dependable furnace performance for all season long. And our services are supported by a 100% Satisfaction Guarantee for a year.* For more details about furnace short cycling, or to schedule HVAC repair, reach us at 301-747-3140 now! 

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*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.