Why Won’t the Burners in Your Furnace Light?

This is a situation nobody wants to run into during a cold winter in Colorado: going to adjust the thermostat so the furnace will come on, but the furnace’s burners simply won’t light. Without lit burners, the furnace won’t provide any heat.

If this happens to you, you may need to call our expert technicians to handle furnace repair in Colorado Springs, CO. If you can’t find a simple reason for the furnace’s failure, such as a dirty filter (we’ll talk about this more in a moment), please don’t attempt to do any repairs on your own since it’s potentially very dangerous. Our technicians will quickly diagnose the problem and have your furnace restored.

Below are several of the most common causes of furnace burners failing to light.

A clogged furnace filter

When the filter for a furnace becomes extremely clogged with dust and other debris, which takes about one to three months, it will block airflow into the furnace. This causes numerous problems for the furnace, such as cutting off the airflow necessary for the burners to light. Change out the filter to see if this solves the problem (and remember to keep up with regular changes in the future).

Faulty thermostat

The thermostat may have lost its connection to the furnace and is unable to send the signals to start the heating cycle that ignites the burners. The thermostat may also have a miscalibration so that its sensors aren’t detecting the accurate temperature of the house, so it won’t register that it should turn the burners on.

Defective flame sensor

The flame sensor is an important safety feature of a gas furnace. This device registers if the burners have ignited once the heating cycle has started. If the flame sensor doesn’t detect flames from the burners, it will shut off the gas flow to them to prevent unburned gas from flooding the combustion chamber. However, if the sensor is faulty, it may shut the gas off no matter what, preventing the burners from lighting at all. Technicians can clean the sensor or replace it as necessary.

Gas line trouble

The burners may not be receiving much or any gas to them because of issues with the gas lines. A stuck gas valve, blockages in the gas line, or gas line leaks are all potential sources of this problem. You’ll definitely want experts to investigate this. If you detect the “raw eggs” odor of natural gas, immediately leave your house and contact the local gas company.

Broken electronic ignition system

Electronic ignition systems have replaced pilot lights in most furnaces (although you may still have a pilot light in your furnace if it was built before 2010). If the igniter burns out or cracks, it won’t be able to light the burners, which will then cause the flame sensor to shut off the gas flow. Our technicians can easily replace a failed igniter to remedy this.

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