Why Is Your Furnace Short Cycling?

As winter approaches, you must ensure that your furnace works because you'll need it to keep your family warm and comfortable. So, if your furnace turns on and off after every few minutes, you should get it checked. But what could be the reason for your furnace short cycling? Well, this article explains it all.


A furnace that overheats will constantly have short cycling problems. Your furnace is designed to shut down when it overheats. It's a safety mechanism that allows the furnace to protect itself. So, if your furnace turns itself off prematurely, call an HVAC professional to check why there is an overheating problem. Overheating may be due to a cracked heat exchanger, dirty air filters, or faulty temperature sensors.

Faulty or Dirty Flame Sensors

If your furnace has faulty flame sensors, it will definitely experience short cycling problems. If the flame sensors fail to sense a flame, they automatically close the gas valve. This is a safety mechanism to prevent gas fires. 

Once the gas supply is shut down, the furnace will also turn off. So, until you get the flame sensors restored or repaired, you'll always have to deal with short cycling. Therefore, you must hire a furnace repair expert to check whether the sensors are dirty or corroded.

You Have a Very Large Furnace

If you own a more oversized furnace than your home, you'll experience a couple of problems. Surprisingly, short cycling is one of the problems of owning an oversized furnace. Remember that the furnace will heat your rooms pretty fast and unevenly. 

And once the thermostat senses that the intended temperatures have been attained, the furnace will shut down. Unfortunately, the uneven heating will turn on the furnace a few minutes after it shuts down. If your furnace has been short-cycling because of its large size, you must replace it, as it's the only way to solve the problem.

Dirty Filters

People underestimate the consequences of having dirty filters in their furnaces. You should never go for months without changing your air filters. In any case, dirty filters will cause a lot of problems when you need your furnace most. Surprisingly, the filters could be the reason your furnace has been short cycling. 

Dirty filters will block the hot air, meaning it will be retained in the furnace, causing its temperatures to rise. And once the furnace overheats, the sensors will trigger it to turn itself off. Once the furnace cools, it will turn itself back on, and the cycle will continue. That said, you need to swap the filters for new ones to solve the short cycling problem.

Speak to a contractor to learn more about residential furnace repair.

About Me

Perfecting My Home HVAC System

After dealing with almost constant air conditioner and furnace failures, I realized I might not be doing my part to keep my systems clean and operational. To sort out the issues, I turned to a professional repairman for help. He explained that since I wasn't changing the filters regularly, there was no telling what would happen. I learned how to clean evaporator coils, replace filters, and even sort out power failures on my own. I want other people to experience the confidence and comfort that comes along with protecting your own HVAC system, so I put up this blog.