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

Your furnace keeps your you cozy during the frigid winter months, so it’s disconcerting when something is wrong. One routine complaint is a furnace that continuously turns on and switches off again. This problem is referred to as short cycling. It stresses your heating system and could lead to costly repairs or even earlier than normal breakdowns.

Short cycling can be the result of for varying reasons. Before you request furnace repair, consider the likely causes and how to fix the problem.

1. Dirty Air Filter

The HVAC filter attracts airborne dust, hair and other pollutants that could wreak havoc on furnace. If you don’t get a new filter often enough, it can eventually be filthy and reduce the airflow. When this takes place, a safety device shuts off the furnace to prevent getting too hot. Check the filter, and if it’s dirty, install a new one. Going forward, install a new filter every 30 to 90 days to prevent your furnace from short cycling.

2. Obstructed Air Vents

A dirty filter isn’t the only issue that can restrict airflow and overheat your furnace. Walk around your home and check for closed or blocked air vents. For recommended system balance and performance, keep all registers open, even in unoccupied rooms.

3. Dirty Blower Wheel

The furnace blower uses blades that move air through the ductwork. If they are caked with dirt, the air won’t travel properly, leading to overheating and short cycling. Routinely changing the filter is the best method to prevent 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 brain of your HVAC system and instructs the furnace on what to do. Ensure 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 bright sunlight or near a heat source that could impact the temperature reading. If you have a smart thermostat, go to the manufacturer’s site for troubleshooting tips.

5. Dirty Flame Sensor

The flame sensor is responsible for turning off the gas valve when no burner flame is present. The sensor can’t detect the flame if it’s sooty, so the gas switches off prematurely and the furnace shuts down. Leave the work of cleaning a dirty flame sensor to a professional like Service Experts Heating & Air Conditioning.

6. Oversized Furnace

When it comes to heating and cooling equipment, larger isn’t always better. A larger system adds warmth to your home too quickly, creating intolerable temperature changes and short cycling. The only way to fix this issue is to request new furnace installation.

If you go through the solutions we went over here to no avail, it’s time to contact the Experts at Service Experts Heating & Air Conditioning. We’ll review the situation, diagnose the cause, and perform the necessary service. Our goal is to bring back indoor comfort, energy efficiency and trustworthy furnace performance for all season long. And our repairs are backed by a 100% Satisfaction Guarantee for a year.* For more information about furnace short cycling, or to schedule HVAC repair, call us at 925-364-5427 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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