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

Your furnace keeps your house cozy during the frigid winter months, so it’s frustrating when something is off. One routine situation is a furnace that continually switches on and turns off again. This problem is called short cycling. It overworks your heating system and might lead to costly repairs or even earlier than normal replacement.

Short cycling can be caused by for varying reasons. Before you book furnace repair, review the likely causes and how to fix the problem.

1. Filthy Air Filter

The HVAC filter traps airborne dust, hair and other substances that could wreak havoc on furnace. If you don’t get a new filter frequently, it can get filthy and decrease the airflow. When this happens, a safety device switches off the furnace to avoid getting too hot. Pull Out the filter, and if it’s dirty, get a new one. From now on, 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 thing that can lower airflow and overheat your furnace. Walk around your home and be on the lookout for for closed or crowded air vents. For recommended system balance and performance, keep all registers open, even in unused rooms.

3. Dirty Blower Wheel

The furnace blower consists of blades that push air through the ductwork. If they are covered in dirt, the air won’t travel properly, causing overheating and short cycling. Routinely replacing the filter is the easiest approach 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 core of your HVAC system and gives the furnace instructions on what to do. Make sure the thermostat is on heating mode and auto fan with the desired temperature showing on the screen. Try putting in new 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, check the manufacturer’s site for troubleshooting instructions.

5. Sooty 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 covered in soot, so the gas switches off too soon and the furnace shuts off. Leave the adjustment of cleaning a sooty flame sensor to a professional like R & M Climate Control Service Experts.

6. Oversized Furnace

When it includes home comfort equipment, oversized isn’t always right. A bigger system warms up your residence too fast, leading to intolerable temperature fluctuations and short cycling. The only way to resolve this problem is to request new furnace installation.

If you attempt the fixes we covered here and you’re still having problems, it’s time to reach the pros at R & M Climate Control Service Experts. We’ll review the situation, diagnose the cause, and perform the necessary repair. Our aim is to restore indoor comfort, energy efficiency and dependable furnace performance for the rest of the season. And our services are upheld 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 865-229-6176 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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