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

Your furnace keeps your house warm during the harsh winter months, so it’s frustrating when something is off. One common issue is a furnace that continually switches on and switches off again. This issue is called short cycling. It strains equipment and may cause pricey repairs or even earlier than normal failure.

Short cycling can be the result of for a few reasons. Before you book furnace repair, review the likely causes and how to fix the situation.

1. Dirty Air Filter

The HVAC filter attracts airborne dust, hair and other substances that could cause problems for furnace. If you don’t replace the filter frequently, it can get clogged and block the airflow. When this takes place, a safety device shuts off the furnace to stop overheating. Inspect the filter, and if it’s dirty, get a new one. From now on, get 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 home and check for shut or obstructed air vents. For adequate system balance and performance, keep all registers open, even in empty rooms.

3. Dirty Blower Wheel

The furnace blower uses blades that push air through the ductwork. If they are caked with dirt, the air won’t flow properly, creating overheating and short cycling. Frequently changing the filter is the best way to avoid a dirty blower wheel. If the blades are already dirty, request furnace maintenance to have them cleaned.

4. Faulty Thermostat

Examine your thermostat next. This is the cortex of your HVAC system and gives the furnace instructions on what to do. Double-check 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 bright 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 tips.

5. Dirty 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 shuts off too soon and the furnace shuts down. Leave the job of cleaning a sooty flame sensor to a professional like Stevenson Service Experts.

6. Oversized Furnace

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

If you try the solutions we covered here and you’re still having issues, it’s time to contact the Experts at Stevenson Service Experts. We’ll examine the situation, figure out the cause, and provide the necessary service. Our aim is to reintroduce indoor comfort, energy efficiency and reliable furnace performance for all season long. And our services are backed by a 100% Satisfaction Guarantee for a year.* For more information about furnace short cycling, or to schedule HVAC repair, give us a call at 614-334-3192 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.

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