What causes a 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.

What does it mean when your furnace turns on and off?

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.

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 long should a furnace run between cycles?

10-15 minutes
Most systems should run about 2-3 cycles per hour. How long should the furnace or AC run in a given cycle? Typically 10-15 minutes in mild weather. The closer you get to the max design temperature in heating (0 Degrees) or cooling (90 Degrees) the longer the run cycle will be.

What might be the problem if the furnace runs but with short cycles?

A short cycling furnace can cause your home heating system to break down prematurely, which can be a big problem during the winter months. If your furnace is short cycling and you can’t seem to get the problem under control, contact the heating contractors at a professional furnace repair service today.

Why does my furnace only run for a few seconds?

A common reason a furnace short cycles is because the heat exchanger, the part that heats your air, is getting too hot due to a lack of airflow. Once the heat exchanger overheats, it trips the high limit switch, which shuts the furnace down to protect it.

Why does my furnace keep running?

The Furnace Filter is Dirty If the filter is dirty, it restricts airflow across the heat exchanger, which causes it to overheat! The furnace goes into “cool down” mode and runs the fan constantly. Your furnace might even start blowing cold air if this is the problem. The solution is simple: replace the furnace filter.

Is it normal for my furnace to turn on every 10 minutes?

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.

How often should a high efficiency furnace run?

A high-efficiency furnace should be running at least 80\% of the day if not longer.

Do high efficiency furnaces run more often?

High efficiency furnaces run more often to save energy and reduce your utility bills. By running more consistently, the furnace can operate at an even pace throughout the day rather than working hard in spurts.

What do I do if my furnace is short cycling?

Once the sensor becomes contaminated with dirt, it will be unable to detect the presence of flames and will shut the furnace off. 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.