If you’ve heard your furnace come on and then turn immediately off, only to come on again a minute later without heating your house, that’s a sign that your furnace is having an issue. If this sounds like your furnace, then you probably have a Short Cycling Furnace. This is not normal and there are several reasons this could happen. 

Calling Edwards Royal Comfort can help fix your furnace problems. As heating and air conditioning experts with years of experience and a proven track record of success, we promise you’ll be 100% satisfied with our outstanding service and value.

What Is a Short Cycling Furnace?

Furnaces have fail-safes and regulators that prevent carbon monoxide and gas from accumulating in your home. Your furnace should kick on and stay on until it reaches the temperature set on your thermostat. Short cycling occurs when your furnace turns on between four and seven seconds and then shuts off without heating your home.

Why Is My Furnace Short Cycling?

A furnace can short cycle for many reasons. Here are some of the most common causes:

Malfunctioning Thermostat

The location of your thermostat is important for accurate temperature readings in your home. If your thermostat is near your furnace, it might only be reading the temperature in the warmest part of the house. Make sure your thermostat is a few rooms away from your furnace for the most accurate readings.

The more likely cause, though, is your thermostat could be malfunctioning. Some thermostats run on batteries, so see if you can replace them. If not, the wiring might be faulty or you might have an old thermostat that needs to be replaced.

Fan Limit Switch Failure

A fan limiter prevents the heat exchanger from becoming hot enough to start a fire or damage the heat exchanger itself. Cracks in the heat exchanger can lead to carbon monoxide leaks. If the fan limiter is not working properly, it could cause your furnace to short cycle.

Blocked Exhaust Vent

If your flue or exhaust vent pipe has been damaged or clogged, this can cause furnace issues. If this is the case, the flue limiter will shut down the furnace to protect you from carbon monoxide and other dangers. A common cause of a blocked exhaust fan is an animal or bird’s nest.

Clogged Air Filter

Every furnace has a filter, and if you haven’t changed yours in the last six months, then this could be why your furnace short cycles. A clogged or dirty filter struggles to pass air through your furnace to the heat exchanger. This may cause the heat exchanger to overheat, tripping the fan limiter, and shutting down your furnace. You can buy replacement filters for your furnace at most home improvement stores. 

Damaged Ignitor

If your furnace runs on gas and your ignitor is damaged, your furnace will shut down to prevent gas accumulations and leaks. 

Dirty Flame Sensor

If your flame sensor is rusted or dirty, the buildup of dirt can cause an irregular furnace cycle. If your flame sensor cannot detect the flame, it will shut off the furnace to prevent gas accumulations that could start a fire. 

Oversized Furnace

If your furnace is too big for your home, it may cycle on and off frequently. This isn’t dangerous, but you could be wasting money on energy usage and higher utility costs. Finding the right sized furnace is important when making a purchase.

Common Fixes

While some of these issues can be fixed by simply changing a filter, most of them need to be performed by a professional. To ensure that your furnace is working properly, it’s important to get it inspected regularly before winter. It’s easy to remember when you sign up for a regular seasonal “Smart Choice” Service agreement. The pros at Edwards Royal Comfort will inspect both your furnace and air conditioner to make sure you’re comfortable in every season. As part of your inspection, we will clean your equipment to ensure it’s running efficiently. 

Call Edwards Royal Comfort to Stay Warm This Winter

Now is the perfect time to schedule your seasonal furnace inspection before you’re left out in the cold. If your furnace is short cycling, call Edwards Royal Comfort. We can take care of any heating and cooling issues you have.

Skip to content