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

Your furnace keeps your house comfortable during the harsh winter months, so it’s frustrating when something isn’t quite right. One common issue is a furnace that continually switches on and switches off over and over. This problem is known as short cycling. It overworks equipment and might cause pricey repairs or even earlier than normal replacement.

Short cycling can be the result of for several reasons. Before you book furnace repair, research the potential causes and how to take care of the problem.

1. Filthy Air Filter

The HVAC filter attracts airborne dust, hair and other substances that could wreak havoc on furnace. If you don’t replace the filter regularly, it can eventually be dirty and block the airflow. When this happens, a safety mechanism turns off the furnace to prevent getting too hot. Pull Out the filter, and if it’s dirty, replace it. From now on, change 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 thing that can restrict airflow and overheat your furnace. Walk around your house and check for unopened or obstructed air vents. For recommended system balance and performance, keep all registers open, even in unused rooms.

3. Dirty Blower Wheel

The furnace blower has blades that push air through the ductwork. If they are dirty, the air won’t move correctly, creating overheating and short cycling. Routinely putting in a new the filter is the simplest way to stop a dirty blower wheel. If the blades are already dirty, book furnace maintenance to have them cleaned.

4. Faulty Thermostat

Inspect your thermostat next. This is the core 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 shown on the screen. Try changing the batteries. Also, check whether the thermostat is in full sunlight or near a heat source that could affect the temperature reading. If you have a smart thermostat, check the manufacturer’s site for troubleshooting tips.

5. Soot-Covered Flame Sensor

The flame sensor switches off the gas valve when no burner flame on. The sensor can’t find the flame if it’s covered in soot, so the gas switches off prematurely and the furnace shuts off. Leave the job of repairing a sooty flame sensor to a professional like Sunbeam Service Experts.

6. Oversized Furnace

When it involves HVAC equipment, larger isn’t always better. A bigger system adds warmth to your residence too fast, creating uncomfortable temperature swings and short cycling. The only way to fix this issue is to do new furnace installation.

If you try the fixes we covered here and you’re still having issues, it’s time to call in the professionals at Sunbeam Service Experts. We’ll examine the situation, figure out the cause, and perform the necessary repair. Our priority is to bring back indoor comfort, energy efficiency and reliable furnace performance for all season long. And our work is upheld by a 100% Satisfaction Guarantee for a year.* For more info about furnace short cycling, or to request HVAC repair, reach us at 716-427-6807 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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