With average winter lows dipping to 16 degrees, a reliable furnace is essential in Northern Illinois. However, furnace short cycling can prevent your furnace from properly heating your home. A short-cycling furnace can also indicate bigger mechanical issues, so it’s important to sort the problem out quickly.
We’ll explore what short cycling is, why it’s an issue, and common causes of furnace short cycling. We’ll also take you through the troubleshooting steps so you know when to call a pro.
What Is Furnace Short Cycling?
Furnace short cycling refers to a furnace that turns on and off repeatedly without actually reaching the desired temperature. For example, if you’ve set your thermostat to 70 degrees, a furnace that short cycles may shut off at 65 degrees.
Short cycling can also refer to your furnace turning on and off too frequently, even if it does reach the desired temperature. A normal functioning furnace will turn on and run for several minutes until it reaches the set temperature. In most furnaces, a normal on-and-off cycle happens up to eight times per hour during the coldest months. However, if your furnace turns on and shuts off after only a minute or two, this is considered short cycling.
Why Short Cycling Is a Problem
Short cycling is an issue for two reasons: it can prevent your furnace from properly heating your home and also puts undo wear on your furnace. Even if your furnace manages to reach the desired temperature, the rapid on-and-off cycle wears out internal components and shortens the lifespan of your furnace.
Common Causes of Furnace Short Cycling
A variety of underlying issues may cause short cycling. Some of the most common causes include:
Dirty or clogged air filters
The most common cause of short cycling is an issue with your air filters. When furnace filters are clogged or dirty, they limit the amount of air intake to your furnace. This causes the heat exchanger to overheat, triggering your furnace to turn off.
Broken thermostat
If your air filters are clean, the next most straightforward check is your thermostat. Old batteries or a faulty thermostat can send the wrong signals to your furnace, preventing it from reaching the desired temperature.
Dirty flame sensor
Your furnace contains a flame sensor that controls fuel flow to your furnace. If this sensor becomes dirty, the safety mechanism triggers your furnace to shut off to avoid a buildup of gas inside the furnace.
Improperly sized furnace
If your furnace is too large or too small for your home, it may short cycle to try to accommodate. A furnace that’s too big can shut off prematurely to avoid overheating your home, while a furnace that’s too small will work too hard and have to shut off to avoid mechanical issues. If your home’s furnace is the wrong size, the most efficient long-term solution may be a new heater installation.
How To Troubleshoot Furnace Short Cycling
If your furnace is short-cycling, try these steps to help diagnose the issue:
Step one: Clean your air filters
The first step in almost all furnace troubleshooting is to check your air filters. Energy Star recommends checking your furnace filters at least once a month. Changing your filters every three months or as the manufacturer recommends is a good idea.
Step two: Check the thermostat
Next, check that your thermostat is working properly. Change the batteries, reset the temperature, and wait a few hours to see if your furnace improves.
It can also be helpful to check the location of your thermostat. If your thermostat is directly in a sunbeam or beside a heater, it may think your home is warmer than it is. This can signal the furnace to turn on and off again.
Step three: Call a pro
If your air filters and thermostat are working well, the next step is to call a pro to examine the internal furnace components. Generally, if you have to unscrew anything to access a furnace part, it’s safest to leave it to a licensed HVAC professional.
Importance of Professional Maintenance
Professional maintenance helps to prevent short cycling. Regular furnace maintenance keeps your air ducts clean and flowing properly, reducing the likelihood of clogs that can cause short cycling.
Routine inspections also catch issues that can lead to short cycling, such as a dirty flame sensor or a mechanical issue. These measures are important for more than just short cycling — they also help prevent safety concerns like gas leaks and fires. Professional furnace maintenance maintains the comfort of your home and the safety of your furnace by keeping it clean, tuned up, and efficient.
When To Seek Professional Furnace Help
If you suspect your furnace is short-cycling, the first step is to check your air filter and thermostat. However, if neither fixes the issue, call an HVAC pro.
You can recognize furnace short cycling by timing your furnace. Start the timer when your furnace turns on — a normal heating cycle will run anywhere from seven to twenty minutes. If your furnace turns on for only a minute or two, it’s probably short cycling.
It’s also important to call a professional if you notice unusual smells or noises coming from your furnace, or if your furnace isn’t heating your home properly. A furnace inspector can diagnose the issue and advise you on furnace repairs or replacement.
Having Issues With a Furnace That Is Short Cycling? Contact the Professionals at G & R Heating and Air
A short cycling furnace can be noisy, expensive, and inefficient at heating your home. That’s why our team of licensed professionals is on hand to solve all your furnace issues. Whether you’re worried about short cycling, looking for repairs, or have questions about how to make your furnace more efficient, our HVAC technicians deliver the expertise you need.
The G & R Heating and Air team serves the greater Chicagoland area to provide reliable furnace solutions for Northern Illinois. Contact us today for a free second opinion or to schedule your next appointment.
