Quick Answer: Why Does My Furnace Short Cycle

A dirty air filter is the most common cause of short-cycling. If your air filter is clogged with dirt, it won’t allow proper air flow to the heat exchanger. That can cause the furnace to overheat and forces the high limit switch to ride to the rescue by shutting the furnace off.

How do I stop my furnace from short cycling?

The easiest way to fix a furnace that is short cycling is to remove the flame sensor to clean it. Use a sponge or brush to remove the dirt from the sensor. After the part is clean, follow the manufacturer’s instructions to insert the flame sensor into the furnace.

How do you fix short cycling?

How To Stop and Prevent Short-Cycling Check your air filter. Believe it or not, a clogged air filter can cause a wide variety of air conditioning issues. Check your thermostat placement. Check your air conditioner’s refrigerant levels. Replace the low-pressure control switch. Check the compressor.

Is short cycling bad for a furnace?

Short cycling doesn’t necessarily pose a threat to your health, but it can absolutely destroy the furnace if it isn’t properly addressed in time.

What causes the furnace to short cycle?

The most likely cause of short cycling is the fan limiter, which prevents fires and furnace damage by shutting the system down if the heat exchanger becomes too hot. A dirty flame sensor or damaged thermocouple will shut off the gas valve and the furnace. This prevents natural gas accumulations that could cause a fire.

Why is my furnace coming on every 5 minutes?

A dirty filter can cause the furnace to overheat. Short cycle time: 2-5 minutes. If the furnace gets too hot, the switch shuts down the furnace. A dirty filter prevents a flow of fresh, cool air into the furnace to be heated and dispersed.

How many times an hour should my furnace cycle?

If your furnace is operating correctly, it should cycle about 2 to 3 times per hour. How long it operates depends on how cold it is outside. In milder temperatures, it may run for 10 to 15 minutes. The colder it gets, the longer the run cycle will be.

Why is my furnace kicking on and off?

Short cycling is a tell-tale sign of a furnace that is too big for your home. Large furnaces rapidly heat the space, resulting in a shorter heating cycle. When the furnace kicks on and off quickly every time it operates, components wear out faster, leading to more frequent repairs, not to mention energy waste.

Is short cycling bad?

The biggest problem with short-cycling is that it increases wear and tear on your air conditioner. Sure, short-cycling is a warning of a problem–like a refrigerant leak. Your air conditioner’s compressor accumulates extensive wear and tear which can cause the system to overheat and burn-out as a result.

How do you know a thermostat is bad?

HVAC system won’t turn on: The most obvious sign of a bad thermostat is that the HVAC system in your building won’t turn on or respond to the thermostat. You should be able to turn on your heating or cooling system from the thermostat, or change operation back and forth from heating to cooling.

How do I know if furnace is short cycling?

Here are the top signs that your furnace may be short cycling. Thermostat Is Malfunctioning. If your thermostat is malfunctioning, it will give incorrect readings to your furnace. The Area Around the Furnace Is Hot. Short Bursts of Heat.

Can thermostat causing short cycling?

Your thermostat could also cause the HVAC system to cycle on and off rapidly, a process known as short cycling. Your furnace or central air conditioner spends a good amount of energy simply turning on and off, which is why you want yours to run for at least 15 minutes at a time before shutting off.

Why does my furnace turn on and off every few minutes?

Dirty or faulty flame sensor If your furnace turns off after a few minutes, there is a good chance it is caused by a faulty or dirty flame sensor. This vital component is designed to keep an eye on the gas burner. When it cannot sense that burner, the furnace runs then shuts off and starts again.

How long should a furnace run per cycle?

With all that being said, if there are no extreme factors involved, the average run time for a furnace is 10-15 minutes per cycle. Your furnace may need to run two to three times an hour to maintain your desired temperature if your home has average insulation.

Why won’t my furnace shut off?

If it’s cold, that means that your furnace is not running but the air handler is still blowing air. If the air that the furnace is blowing is hot, that means that the furnace burners aren’t turning off. Two very common causes are that the thermostat is set too high, or the filters being dirty.

Why do I have to keep resetting my furnace?

If a furnace isn’t receiving enough airflow, it may overheat and trigger the reset button to trip. Make sure to clean or replace the air filters and keep the air vents open enough for proper airflow. A clogged or dirty air filter may cause the furnace to trip.

Why does my heat keep kicking on?

When a furnace keeps turning on and off, it is usually due to short cycling. This is the term used to describe problems originating from within the heating system. If short cycling is not promptly diagnosed and corrected, it could cause permanent damage to your heating unit and higher utility bills.

How often should a gas furnace cycle on and off?

Answer: A gas furnace should cycle on and off 3-8 times an hour ideally. That’s usually the most common case with furnaces.

Why does my furnace turn off after 15 minutes?

Short-cycling is when a heater doesn’t complete its regular heating cycle and turns off early. A full heating cycle for a furnace or heat pump is usually around 15 minutes or more. If your heater keeps turning off after only five minutes, that’s too short—no matter how low you’ve set the thermostat.

Is it OK to run the fan on the furnace?

Even if you have a single story home, you should still run your furnace fan. Running your furnace fan will blend the air throughout the day keeping the air in your home from having noticeable hot and cold spots.

Can a bad blower motor cause short cycling?

Air handler defects ranging from a dirty air filter to dirty blower or wrong blower speed can prevent the furnace from producing enough heat rise across the heat exchanger, causing overheating and short cycling at the heating furnace.