Want to work for a great team with great perks? Click to learn more Read More

Skip navigation

After Hours Service Available


Serving Courtenay, BC and Surrounding Areas

After Hours Service Available


Serving Courtenay, BC and Surrounding Areas


Temprite Climate Solutions Blog

Why Is My Furnace Shutting Down Early?


When you need your home’s gas furnace working, the last thing you want to happen is to have it keep shutting down on you. Unfortunately, this is one of the more common furnace issues you may run into: burners that won’t stay lit. There may be a simple explanation for it, but in many cases you’ll need to call us for professional furnace repair in Comox, BC. Please do not attempt to make any repairs to a gas furnace on your own, as it’s potentially hazardous.

So why aren’t the furnace burners staying lit? Let’s examine some of the possibilities:

Insufficient airflow into the furnace

For the burners to ignite, they need airflow. The airflow into the furnace comes from the blower fan that draws air through the return air ducts. But if this airflow is choked off because of a clogged furnace filter or faulty blower, the burners may not be able to stay on for long. A faulty blower needs professional repairs, but you can change out the filter yourself.

Faulty flame sensor

This is a common cause of burners that won’t stay on. The flame sensor is a safety precaution in a gas furnace that tests that the gas coming from the burners has ignited. If the sensor does not detect flames, it will automatically shut off the gas flow to prevent unburned gas from flooding into the combustion chamber. If the flame sensor malfunctions, it will mistakenly sense the burners haven’t ignited and shut the gas off anyway, causing the burners to go out. The flame sensor may be dirty or may need to be replaced entirely.

Dirt and grime on the burners

The flames from the burners may be going out because they’re struggling to draw enough oxygen for combustion through excess dirt or other grime along their surface. This is often a problem in a furnace that hasn’t received regular maintenance. During maintenance, our technicians will inspect the burners to see if they require cleaning. Please don’t attempt to clean the burners yourself, since this requires detaching the burner assembly first. 

The heat exchanger is overheating

The reason the burners are going out may be due to another safety feature: the limit switch, which activates when the heat exchanger becomes too hot. The limit switch will shut off the gas as well as the power to the furnace. This could be another issue due to a clogged filter (not enough airflow is moving around the heat exchanger to cool it down), but it may also be a problem with the furnace failing to properly vent combustion gas from the heat exchanger—and this is an issue you want professionals to fix as soon as possible. 

Faulty control board

The control board is the component of the furnace that regulates when other components turn on and off. If the control board is faulty, it can cause the burners to shut off after only a short period of time. Professionals can examine the control board to see if it can be fixed or replaced.

If you need furnace repair, call Martin Heat & Air. We’re more than HVAC services; we give you peace of mind.

Comments are closed.