A good way to tell if your furnace is short-cycling is if your heater turns on and off several times repeatedly without producing any heat. A furnace that is the right size for the home and working properly cycles approximately three to eight times per hour.
They are designed to cycle on and off, but a standard home furnace should only turn on and off between three to eight times per hour. That means normal heating cycles last from seven to 20 minutes. You can tell your furnace is short-cycling if that on/off cycle happens every couple of minutes.
The system will turn off prematurely and then quickly turn back on in an attempt to reach the set temperature. The thermostat will incorrectly tell the unit that the set temperature was reached or vice versa.
With an effective air delivery system and a well-insulated home, this should be long enough to establish your preferred temperature throughout the building. After resting for approximately five to 10 minutes, your furnace will likely cycle on again.
If your furnace turns on, and off, and back on again in a seemingly endless loop, you're experiencing short cycling.
This means the compressor will run for 10 minutes, stop for 10 minutes, and repeat the cycle two more times during a single hour. You can tell a system that's short cycling when it turns on and off three times in five to ten minutes.
The simple solution: Turn your furnace off and check the filter. If it's dirty or it's been 3 months or more since you changed it, put a new, high-quality filter in place. Turn the furnace on again.
Furnaces typically run for about 10 to 15 minutes in moderate weather. Extreme cold can result in longer cycle times. Positive and negative factors that can affect furnace run time include: Sizing: A furnace correctly sized for heating the area operates more efficiently.
Leave the breaker(s) off for at least 10 minutes while the system is off and “rebooting.” After 10 minutes have elapsed, go back to the breaker box and flip the HVAC breaker(s) back on.
If your furnace is overheating, it could be shutting off prematurely before it reaches your desired temperature when the temperature safety limit is reached.
Short-cycling is when a furnace or boiler keeps turning on then off for very short durations. A “short duration” in this instance is generally defined as less than a minute up to a few minutes long. Some short-cycling heating systems will turn on and off after just a few seconds.
Dirty air filters, loose electrical connections, and frozen evaporator coils are among the most common things that lead to short cycles. You may be able to resolve sources of short cycling yourself, while other causes will require a professional repair.
Troubleshooting Tips For Stopping A Short Cycling System
Check the condition of the filter and replace it with a new one if the existing filter's surface is dirty. Simply changing the filter can help fix the issue and improve your system's efficiency.
Your thermostat plays a crucial role in regulating your heating system's operation. If it's malfunctioning or improperly calibrated, it can cause short cycling.
If the lights are still illuminated or flashing with the flame sensor wires disconnected, the primary control is defective and should be replaced.
Find the switch mounted on or near the furnace and turn the power off. If you can't find a switch at the furnace you can turn off the circuit breaker to the furnace at the main circuit breaker box. Wait about 10 seconds. Turn the switch or breaker back on and check the furnace to see that it has power again.
As soon as you notice the signs of short cycling, check your filter – make sure it is not filled with contaminants and is installed snugly facing the proper direction. If you have a dirty or clogged air filter, change it right away and see if short cycling stops.
While it should cycle throughout the day, clicking on too frequently may indicate a problem. Homeowners often find themselves wondering, "How often should my furnace cycle?" The answer lies in a gray area. On average, furnaces should kick on and turn off anywhere from three to eight times per hour.
The Damage
If the short cycling isn't addressed right away, you could seriously shorten the life of your furnace. As soon as you notice that your furnace is short cycling, turn it off and call for repairs. If your furnace is having a problem with short cycling, call Sound Heating.
Short cycling is a common sign of a bad flame sensor. The sensor thinks that there isn't a flame, so it shuts off the gas as a safety mechanism. Except, there is a flame and without the gas to supply it, it dies. This is a frustrating problem, but an HVAC technician can fix it.
Ask twenty professional HVAC contractors the question, “How Much Does A New Furnace Cost?” and you'll probably get the same answer... “It depends.” On average, the cost of a new furnace can range from $2,000 - $14,2001. However, factors like furnace efficiency, type, size, and much more can impact this range.
If your air filter is clogged or dirty, it can block airflow and make your system work harder, leading to overheating and an early shutdown. Cleaning or replacing your filters regularly is a good idea and a necessary part of your regular HVAC maintenance to keep everything running smoothly.