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

Your furnace keeps your home comfortable during the frigid winter months, so it’s disconcerting when something is off. One routine issue is a furnace that continuously switches on and switches off again. This problem is referred to as short cycling. It strains your heating system and may lead to expensive repairs or even premature failure.

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

1. Clogged Air Filter

The HVAC filter attracts airborne dust, hair and other pollutants that could wreak havoc on furnace. If you don’t replace the filter often enough, it can become filthy and block the airflow. When this occurs, a safety device shuts off the furnace to stop overheating. Inspect the filter, and if it’s dirty, replace it. Going forward, change the filter every 30 to 90 days to prevent 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 home 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 move air through the ductwork. If they are caked with dirt, the air won’t move properly, causing overheating and short cycling. Regularly putting in a new the filter is the simplest way to prevent a dirty blower wheel. If the blades are already dirty, book furnace maintenance to have them cleaned.

4. Faulty Thermostat

Examine your thermostat next. This is the brain of your HVAC system and instructs the furnace on what to do. Double-check the thermostat is in heating mode and auto fan with the desired temperature showing on the screen. Try replacing the batteries. Also, check whether the thermostat is in direct sunlight or near a heat source that could influence the temperature reading. If you use a smart thermostat, check the manufacturer’s site for troubleshooting guides.

5. Soot-Covered Flame Sensor

The flame sensor is responsible for turning off the gas valve when no burner flame going. The sensor can’t detect the flame if it’s sooty, so the gas turns off prematurely and the furnace shuts down. Leave the work of cleaning a faulty flame sensor to a professional like Kingston Home Services by Enercare.

6. Oversized Furnace

When it comes to HVAC equipment, bigger isn’t always better. A larger system adds warmth to your residence too fast, causing intolerable temperature changes and short cycling. The only way to fix this problem is to request new furnace installation.

If you go through the resolutions we covered here and you’re still having problems, it’s time to call in the Experts at Kingston Home Services by Enercare. We’ll review the situation, diagnose the cause, and do the necessary service. Our goal is to bring back indoor comfort, energy efficiency and trustworthy furnace performance for all season long. And our services are upheld by a 100% Satisfaction Guarantee for a year.* For more info about furnace short cycling, or to schedule HVAC repair, call us at 613-817-1591 now!


*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.