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

Your furnace keeps your you comfortable during the harsh winter months, so it’s disconcerting when something is wrong. One routine complaint is a furnace that continuously turns on and shuts back off over and over. This issue is called short cycling. It strains your heating system and might result in expensive repairs or even early breakdowns.

Short cycling can happen for several reasons. Before you book furnace repair, review the probable causes and how to fix the situation.

1. Clogged Air Filter

The HVAC filter attracts airborne dust, hair and other pollutants that could damage the furnace. If you don’t replace the filter frequently, it can get filthy and decrease the airflow. When this takes place, a safety mechanism switches off the furnace to prevent getting too warm. Check the filter, and if it’s dirty, install a new one. Going forward, install a new filter every 30 to 90 days to stop 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 house and check for unopened or blocked air vents. For recommended system balance and performance, keep all registers open, even in unused rooms.

3. Dirty Blower Wheel

The furnace blower uses blades that distribute air through the ductwork. If they are dirty, the air won’t flow properly, causing overheating and short cycling. Routinely changing the filter is the easiest method to prevent a dirty blower wheel. If the blades are already dirty, book furnace maintenance to have them cleaned.

4. Faulty Thermostat

Check your thermostat next. This is the core of your HVAC system and instructs the furnace on what to do. Ensure the thermostat is on heating mode and auto fan with the desired temperature showing on the screen. Try changing the batteries. Also, check whether the thermostat is in bright sunlight or near a heat source that could influence the temperature reading. If you rely on a smart thermostat, visit 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 sense the flame if it’s covered in soot, so the gas turns off sooner and the furnace shuts off. Leave the work of cleaning a sooty flame sensor to a pro like Neal Harris Service Experts.

6. Oversized Furnace

When it includes HVAC equipment, larger isn’t always best. A larger system adds warmth to your house too fast, creating unpleasant temperature fluctuations and short cycling. The only way to resolve this problem is to schedule new furnace installation.

If you go through the fixes we covered here and nothing has changed, it’s time to reach the pros at Neal Harris Service Experts. We’ll review the situation, figure out the cause, and provide the necessary repair. Our priority is to reintroduce indoor comfort, energy efficiency and reliable furnace performance for the rest 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, call us at 816-787-0500 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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