When a furnace will start up, only to quickly turn off before the cycled is finished, this is known as short cycling. Short cycling is often a sign or symptom that there is a problem somewhere in you heating system. Unfortunately, the problem can vary, some of which requires professional repairs while other solutions are simple fixes. Hal Mechanical will share some of the common causes for a furnace to short cycle and what needs to be done to correct them.
Why is My Furnace Heater Short Cycling?
Clogged Air Filter – One of the common reasons why a furnace will short cycle is due to a dirty or clogged air filter. When an air filter is dirty, it will cause stress on the furnace and lead to overheating. When the furnace overheats, it will quickly turn off to prevent major damages to the furnace. This of course is short cycling. The furnace turned off to avoid stress and over heating. To restore your furnace, simply change out your air filters. Make sure to change out your air filters before they get too dirty, This will prevent future problems.
Thermostat Failure – Another common source for your furnace’s short cycling problem may be the thermostat. The thermostat can be malfunctioning or the batteries will need to be replaced. When the thermostat sends out a signal to quickly turn off, it is important to determine the problem. Start by checking the thermostat batteries as well as the setting.
Air Duct Leaks – When a furnace short cycles it is mostly due to stress and overheating. Stress and overheating occur when the furnace has to work more often than normal. This doesn’t allow the furnace to cool down between cycles. One reason why a furnace will overheat and need to run more frequent heating cycles, is due to a leak in the air ducts. When the warm air travels through the air duct, a leak can cause that heat to leak out and not heat up the inside of the home properly. This will, of course, lead to more frequent heating cycles. The air ducts should be inspected every few years for leaks and to maintain and prevent strain of your HVAC system.
Oversized Furnace – Many people are surprised to learn about the number of problems that comes with installing an oversized unit. People assume a bigger unit is better. However, this is not the case. One of the first problems a homeowner will discover with an oversized furnace or heating system, is short cycling. An oversized furnace will never be able to finish a cycle due to the burst of intense heat they produce. Short cycling not only fails to distribute heat evenly throughout the home, but it will reduce the life of the furnace and lead to premature repairs. When your furnace is short cycling a lot, you may want to have the unit size inspected and make sure it is not too big nor too small.