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

Your furnace keeps your home comfortable during the chilly winter months, so it’s annoying when something isn’t quite right. One common situation is a furnace that endlessly turns on and switches off all the time. This issue is known as short cycling. It strains your furnace and could cause expensive repairs or even early breakdowns.

Short cycling can be caused by for a few reasons. Before you request furnace repair, read about the likely causes and how to resolve the situation.

1. Clogged Air Filter

The HVAC filter attracts airborne dust, hair and other substances that could wreak havoc on furnace. If you don’t get a new filter regularly, it can get clogged and block the airflow. When this takes place, a safety device shuts off the furnace to stop getting too hot. Inspect the filter, and if it’s dirty, replace it. Going forward, 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 lower airflow and overheat your furnace. Walk around your house and look for shut or crowded air vents. For proper system balance and performance, keep all registers open, even in empty rooms.

3. Dirty Blower Wheel

The furnace blower has blades that move air through the ductwork. If they are dirty, the air won’t move right, causing overheating and short cycling. Regularly changing the filter is the easiest way to stop 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 shown on the screen. Try replacing the batteries. Also, check whether the thermostat is in direct sunlight or near a heat source that could impact the temperature reading. If you have a smart thermostat, visit the manufacturer’s site for troubleshooting instructions.

5. Dirty Flame Sensor

The flame sensor is responsible for turning off the gas valve when no burner flame on. The sensor can’t detect the flame if it’s coated in soot, so the gas turns off too soon and the furnace shuts down. Leave the adjustment of cleaning a dirty flame sensor to a professional like Service Experts Heating & Air Conditioning.

6. Oversized Furnace

When it includes home comfort equipment, larger isn’t always right. A bigger system adds warmth to your residence too quickly, leading to intolerable temperature fluctuations and short cycling. The only way to fix this issue is to schedule new furnace installation.

If you go through the fixes we mentioned here to no avail, it’s time to call in the pros at Service Experts Heating & Air Conditioning. We’ll review the situation, diagnose the cause, and provide the necessary repair. Our goal is to bring back indoor comfort, energy efficiency and reliable furnace performance for the remainder of the season. And our work is backed by a 100% Satisfaction Guarantee for a year.* For more information about furnace short cycling, or to schedule HVAC repair, call us at 403-279-5760 today!


*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.