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

Your furnace keeps your home comfortable during the frigid winter months, so it’s frustrating when something is wrong. One common complaint is a furnace that continually kicks on and shuts back off all the time. This issue is known as short cycling. It overworks equipment and might cause costly repairs or even earlier than normal failure.

Short cycling can be caused by for several reasons. Before you book furnace repair, read about the potential causes and how to resolve the situation.

1. Filthy 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 eventually be filthy and reduce the airflow. When this happens, a safety mechanism shuts off the furnace to prevent getting too warm. Pull Out the filter, and if it’s dirty, install a new one. Going forward, replace 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 issue that can lower airflow and overheat your furnace. Walk around your house and check for shut or blocked air vents. For proper 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 correctly, causing overheating and short cycling. Regularly replacing the filter is the simplest way to avoid a dirty blower wheel. If the blades are already dirty, request furnace maintenance to have them cleaned.

4. Faulty Thermostat

Inspect your thermostat next. This is the core of your HVAC system and instructs the furnace on what to do. Make sure the thermostat is in heating mode and auto fan with the desired temperature shown on the screen. Try putting in new batteries. Also, check whether the thermostat is in direct sunlight or near a heat source that could affect the temperature reading. If you have a smart thermostat, go to the manufacturer’s site for troubleshooting guides.

5. Soot-Covered Flame Sensor

The flame sensor turns off the gas valve when no burner flame going. The sensor can’t detect the flame if it’s sooty, so the gas switches off too soon and the furnace turns off. Leave the adjustment of cleaning a dirty flame sensor to an Expert like Service Experts Heating & Air Conditioning.

6. Oversized Furnace

When it includes home comfort equipment, larger isn’t always better. An oversized system warms up your home too rapidly, causing unpleasant temperature swings and short cycling. The only way to take care of this issue is to request new furnace installation.

If you attempt the fixes we mentioned here and you’re still having problems, it’s time to reach the Experts at Service Experts Heating & Air Conditioning. We’ll take a look at the situation, pinpoint the cause, and provide the necessary service. Our priority is to restore indoor comfort, energy efficiency and reliable furnace performance for the rest of the season. And our repairs are supported by a 100% Satisfaction Guarantee for a year.* For more information about furnace short cycling, or to schedule HVAC repair, reach us at 954-736-4314 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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