Why does my furnace start then stop and start again?

This behavior is caused by something cutting short each furnace cycle since your furnace is being forced into a short cycle to keep your home the temperature set on your thermostat. A furnace that is sized properly for your home should start and stop 3-8 times in an hour.

Why does my furnace blower keeps turning on and off?





If your blower is constantly turning on/off when the furnace isn’t heating… …you most likely have a bad fan limit switch. Your furnace fan limit switch is basically a control system that determines when the furnace blower assembly should turn on and off.

Why does my furnace only run for a 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 often should a furnace cycle on and off?

3-8 times per hour

On average, furnaces should kick on and off anywhere from 3-8 times per hour. However, if your furnace does so more frequently, don’t assume it’s short cycling just yet.

How do I stop my furnace from short cycling?





Quote from the video:
Quote from Youtube video: So to fix this issue shut off your thermostat. And open up the furnace. And then replace the batteries on the thermostat.

Why does my furnace run every 10 minutes?

It cycles off because an inner safety is getting overheated from inadequate airflow. Either get a smaller furnace or enlarge the duct system to move the amount of air needed by the furnace.

How long should a high efficiency furnace run?

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 do you know if your furnace is short cycling?

If your furnace turns on and off repeatedly for short bursts of time, not allowing the house to reach its proper temperature, it is short-cycling.

Why is my furnace coming on every 5 minutes?



Short cycle time: 2-5 minutes.



Your furnace has a part called a high-limit switch. 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. Without the fresh air, it will quickly overheat.

How do you know a thermostat is bad?

7 Ways to Tell Your Thermostat Is Broken

  1. Thermostat Has No Power. …
  2. AC or Furnace Won’t Turn On. …
  3. Heater or AC Won’t Turn Off. …
  4. Thermostat Doesn’t Match Room Temperature. …
  5. Thermostat Doesn’t Respond. …
  6. Short Cycling. …
  7. Thermostat Forgets Programmed Settings.


Do high efficiency furnaces run more often?



Contrary to what you may initially think, high efficiency furnaces run more often. However, this does not mean that they use more energy. By running more often, they can ensure that your home is kept at a more even temperature without having to work as hard.