Why is my furnace lighting then shutting off?

If your furnace shuts off too often, you could have a corroded or dirty flame sensor. A flame sensor lets your system know there’s a flame when the gas valve is open. If there isn’t a flame, the sensor will shut off the gas valve to keep the gas from getting into your house.

Why does my furnace keep shutting off after a few minutes?





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. This could be a relatively easy fix.

Why does my furnace only turn on sometimes?

Restricted Air Flow



Similar to a clogged air filter, restricted airflow will also prevent the furnace from delivering the proper amount of heated air to the space and will often cause the furnace to cycle on and off on its over-temperature device.

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.

What does it mean when a furnace is short cycling?

Short cycling is when the furnace turns on for a short period of time but then turns off. This start-and-stop cycle can keep your home from properly warming up and may also damage your furnace itself.

Why is my gas furnace short cycling?





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?

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.

How do I clean my furnace flame sensor?

Quote from the video:
Quote from Youtube video: So if you have a situation like this what you have 90% of the time is just a dirty flame sensor. So we'll go through the steps on how to clean it. So the right side of the furnace.

Why does my furnace shut off after 15 minutes?

If your air filter is too dirty, it will restrict airflow. Your furnace will then shut off prematurely to avoid overheating. We recommend replacing flat filters once a month, and pleated filters every three months. It’s easy to stay on top of changing your filter by adding a Filter Reminder on your thermostat.

How do you fix short cycling?



How To Stop and Prevent Short-Cycling

  1. Check your air filter. Believe it or not, a clogged air filter can cause a wide variety of air conditioning issues. …
  2. Check your thermostat placement. …
  3. Check your air conditioner’s refrigerant levels. …
  4. Replace the low-pressure control switch. …
  5. Check the compressor.


Can short cycling damage 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.

Can a dirty flame sensor cause short cycling?



Bad Flame Sensor



When the flame sensor doesn’t sense a flame, it will shut off the natural gas valve to keep it from pumping raw gas into your home, which could lead to deadly gas fires. A bad flame rod shuts off the flame almost immediately after being lit, resulting in a furnace short cycle.

Is short cycling normal?

One of the most common, and unfortunately harmful, problems an air conditioner can have is something called short-cycling. This is both a symptom of a problem and a cause of a problem. Sometimes a few simple adjustments may be all that’s needed to repair the issue.

Is my thermostat causing short cycling?

One of the biggest reasons why your thermostat might be causing your HVAC system to short cycle is due to loose wiring. When your thermostat’s wiring is loose, it can cause your HVAC system to keep switching off and on in irregular but rapid intervals.

How do you fix a short cycling boiler?

Adding thermal mass to the heating system will decrease the burner short cycling and this can be done by adding water volume to the system. A relatively easy way to add thermal mass is adding a “Buffer Tank”. A “Buffer Tank” is simply a tank of water.