Furnace short cycling refers to the switching on and off of your furnace system without reaching the set temperature on the thermostat. And for those experiencing short cycling, you may notice suddenly that your home isn’t as warm as it should, leaving you and your loved ones cold and uncomfortable.
When the temperature in your home drops from the set temperature on the thermostat, a properly working furnace will turn on. From there, the furnace will warm your home until it reaches the temperature on the thermostat and then will turn off. Depending on the condition of your furnace system, the outdoor temperature, and other variables—cycling should only occur three to eight times an hour. However, if your furnace cycles too often, or runs for a minute or two before shutting off, you could be experiencing a problem with your furnace. Here are eight causes of furnace short cycling.
Table of Contents
Why Is My Furnace Performing Short Heating Cycles?
1.) Deterioration to Flame Sensors
During the heating process, when your furnace burns fuel, the system will produce small amounts of water. This overtime can cause metals to corrode and rust.
As a result, corrosion buildup triggers frequent short cycling of your furnace which can be detrimental to the safety of your home. To best avoid this issue, you must clean and inspect your flame sensor. Since this requires working with dangerous flammable gasses and electricity, you’ll need to contact an HVAC professional for a proper inspection of your flame sensor.
If you have faulty temperature-monitoring components, chances are, your furnace can overheat and shut down. Frequent overheating is one of the most common sources of short cycling. Most contemporary furnaces will come equipped with a built-in safety device that regulates temperature.
A faulty heat exchanger can also cause short cycling. In worst-case scenarios, a cracked heat exchanger will emit heat into other components of your furnace. As a result, your furnace may overheat and experience short cycling.
3.) Contaminated Air Filters
Something as simple as a dirty air filter can cause your furnace to short cycle. Contaminated air filters block airflow, and eventually, cause a backup. This means that warm air will remain in the furnace instead of distributed to the different areas of your home. The internal temperature in your furnace will rise, causing your system to shut off. That’s when the excess furnace cycling will occur.
To best avoid this, replace your air filters at the beginning of each filter, or according to your system’s manual so that you won’t experience any blockage. Of course, if you have any questions or concerns about your furnace filter, please speak with a qualified HVAC professional.
Tips & Insights: How to Choose a Furnace Size For Your House
4.) Furnace is Too Large For Home
It’s true. Your furnace can be too big for your home. If you have an oversized furnace, your unit will heat your system quickly and unevenly.
In an effort to maintain a consistent temperature throughout your home, your furnace will start to short cycle. Poor insulation is also another factor in short cycling when it comes to an oversized furnace. Since larger furnaces generate excess heat, most of the heat and energy will escape through holes, cracks, and faulty seals. With that much heating and energy being lost, your furnace will short cycle in order to keep the temperature constant.
A faulty thermostat can be a possible culprit for short cycling. If you’re experiencing a furnace short cycling, the first and easy thing you can do is check your thermostat to see if it’s performing correctly. Many times, a homeowner may forget to switch their thermostat over to the heating mode.
As a result, the system will short cycle. Before examining furnace components, inspect your thermostat to see if it’s in the “heat” position before readjusting. If looking to test your thermostat to ensure it’s working properly, speak with an HVAC professional to get a better examination..
6.) Clogged Flue
At any moment, an object or pest such as a bird can get in your flue or vent pipe and cause a clog. The furnace, in response, will shut down to protect you and your loved ones from poisonous carbon monoxide. This will create short cycling and will need to be addressed immediately.
7.) Damaged Electronic Ignition System
Another reason for short cycling could stem from a damaged hot surface igniter. If you’re experiencing a malfunctioning hot surface igniter or the pilot light is shutting off (especially on an older model) your furnace will shut down instantly to hinder potential gas accumulations.
8.) Air Leaks
Lastly, sometimes the answer is as simple as poor insulation. Before suspecting your furnace system short cycling is coming from a larger issue, examine the windows to see if any of them are open or not sealed correctly. If air is passing through any of these seals, this means that newly heated air from the furnace is escaping through the window. This prohibits your furnace from heating up your home as it should, which can cause short cycling.
To prevent this, you will need to caulk around your window frames so that warm air remains trapped indoors. Of course, if this is not the case, contact an HVAC professional to determine and fix your furnace issues.
How Long Is a Normal Heating Cycle?
To best determine if you’re having a short cycling problem, you should know how a normal cycling process performs.
With a regular functioning furnace unit, the heating process is simple: You set your thermostat to the temperature of your desire. The thermostat will signal the furnace, and with the help of fuel, the burners are lit. The fuel then combusts into hot air, in which the blower fan will direct the hot air through the ducts system and distribute it throughout your home.
A normal cycling process averages about 15 minutes per cycle if making your home just a bit warmer. This cycle will repeat until the home heat to the desired temperature.
Furnace Repair & Installation Services Offered By Fenwick
Is your furnace malfunctioning or simply not working? Properly circulating air not only keeps your home comfortable, it also removes dust and other allergens that can lead to discomfort and illness. At Fenwick Home Services, we care about your comfort. We offer trustworthy and safe furnace repair services to homes in Jacksonville and other areas of Florida. Give our team of licensed technicians a call by phone at (904) 217-5694 to receive assistance with a furnace problem. We are always there to get the job done efficiently and effectively.