Why Your Furnace Is Short Cycling

If you notice your furnace turning on and then off again before heating your home to the temperature set on the thermostat, it might be short cycling. This issue occurs in the winter and may prevent your furnace from producing enough heat to keep your home warm and comfortable. There are many reasons why a furnace can short cycle. To help address this issue, here Home Air Services, one of the top home heating companies, shares the common causes of a short-cycling furnace.  

Bad flame sensor. If you haven’t cleaned your flame sensor recently, this may be the reason why your furnace flame keeps going out right after being lit. Your flame sensor will shut off the natural gas valve if it doesn’t sense a flame to keep it from pumping raw gas into your house. Keep in mind that flame sensors are susceptible to corrosion and rust because your furnace produces small amounts of water during the heating cycle. Thus, be sure to clean your flame sensor regularly. 

Overheating furnace. Another thing you have to watch out for is overheating. If your furnace frequently overheats, it may be turning itself off to avoid potential damage. As such, the thermostat in your furnace may be faulty, causing short cycling and temperature swings. In the worst-case scenario, the thermostat will damage the heat exchanger and release deadly carbon monoxide gas into your home. Carbon monoxide is extremely poisonous, and a leak will put you and your family in grave danger. 

Dirty furnace filter. Your furnace may also short cycle and overheat because a contaminated air filter is preventing warm air from circulating throughout your home. For this reason, your furnace will be unable to heat your home efficiently. If you restrict the air coming into the system, this may lead to a clogged exhaust vent and poor insulation. One way to solve this issue is to check your filters monthly and change them as needed. For best results, you may want to hire a professional HVAC technician for routine heater and air conditioner maintenance. 

Blocked exhaust vent. Items inside and outside your home can find their way into your flue or exhaust vent pipe. This may cause furnace issues if they’ve been damaged or blocked. The flue limiter will eventually shut down the furnace to prevent a carbon monoxide leak and other dangers. The common causes of a clogged vent are bird or animal nests. If this is the case, be sure to call animal control or a pest specialist to get rid of them. During the winter, snow or ice may also block your vent. In this situation, you may want to contact an HVAC professional. 

Oversized furnace. You might think that “bigger is better,” but when it comes to your furnace, this is far from the truth. Take note that an oversized system can short cycle because it distributes air quickly and unevenly. With an oversized furnace, you may also end up wasting your money on energy usage and higher energy bills. Therefore, it’s important to make sure your furnace fits the size of your home. The right size of furnace guarantees long heating cycles and no noticeable temperature swings. 

As one of the leading furnace and duct cleaning companies, Home Air Services is determined to provide the assistance you need for your HVAC needs. Call us today at (301) 585-8100 or fill out our contact form to set up an appointment.