How To Tell If An Igniter On A Gas Furnace Is Working Properly

image of a furnace ignition system

One of the most common problems that occur with a gas furnace is an electronic ignition failure. As a homeowner, you need to be aware of what to do when your gas furnace ignitor not working. Knowing how to detect the problem can help you decide when you need to call in an HVAC contractor.

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Signs Your Gas Furnace Ignition Is Malfunctioning

Below we will cover the warning signs that can help you to detect a problem with the ignition on your furnace. The information in this article should help you to determine if you need to call in a professional or if there is a simple solution available.

Furnace Ignition Systems

Previously, gas furnaces had pilot lights for operation where the light would stay on if the furnace was operating correctly. The gas valves would open to ignite the gas. When the light failed to come on, the heater would not function and the furnace would be unable to produce any heat.

Newer systems use electronic ignition. These modern-day furnaces have either a hot surface ignition or as intermittent pilot system.

A hot surface ignition system uses electricity. When the system gets warm enough, the gas begins to flow into the burner and the ignitor will light up.
An intermittent system uses an electric spark instead. The spark turns the pilot light on and when the sensor detects that it is lit, the valve opens and the burner gets ignited.

These newer systems are more energy-efficient as the pilot light does not remain lit once the furnace is operating correctly.

image of the inside of a heating system


What Happens When An Electronic Ignition Fails?

A failure can occur with the ignition on an electronic gas furnace when the light fails to come on and the burners can not ignite. The furnace will not heat up and no heat will be produced.

Another common problem is delayed ignition, this is often preceded by a loud bang before ignition. This could be a serious safety issue as it could lead to an accumulation of build-up gas if you attempt to turn the ignitor on several times. In this case, you would need to call in an HVAC professional immediately.

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Common Problems With Gas Furnace Ignitions

There are several common problems that can occur with a gas furnace ignitor which we will cover below:

Damaged Furnace Ignitors

Over time ignitors can become damaged from wear and tear or simply because they do not always have the same longevity of the furnace. In this case, a replacement ignitor is needed. It can be difficult for homeowners to tell when a replacement is needed as it requires testing the ignitor using a multimeter. It may also be necessary to remove the ignitor wires. If you suspect that this may be the problem an HVAC technician can do this for you.

Incorrect Furnace Ignitor

If your furnace was installed incorrectly then it could be that an ignitor with the incorrect voltage was used. This could lead to the failure of the ignition.

Temperature Limit Switch

To prevent overheating, furnaces have a limit switch that will turn the ignitor off if the temperature gets too high. A simple issue could be that the limit switch is not working correctly or alternatively the air filters on the furnace could be clogged up. Clogged filters can cause the limit switch to turn the ignitor off prematurely.

image of a furnace circuit breaker repair


Power Surges

An electric ignitor can be prone to damage when power surges occur. If power surges are frequent they can cause the ignitor to burn out especially in hot surface ignition systems due to the burning filaments they use.

Troubleshooting Your Furnace Ignitor

Below are some simple tips for troubleshooting your furnace ignitor. The following steps are usually part of a regular furnace maintenance checks to help keep your system working efficiently.

Power Check

The problems could be a lack of power to the system. The circuit breaker usually causes this issues. Check that your power source is connected and the furnace is powered.

Resetting The Ignitor

You can reset the ignition on your furnace simply. To do this you must cut the power to the furnace first by turning off the circuit that powers it. Once the power is off you can remove the burner door to reveal the ignitor. Turn this to “off” and leave it off for at least 5 minutes. After this time, turn the ignitor back to the “on” position and replace the burner door. You can then turn the power source back on and restart the furnace.

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Calling An HVAC Professional Contractor

Whenever you experience issues with your heating system, particularly with Gas furnaces, it is advisable to call in an expert. Heating systems can become a serious safety issue if they malfunction and it can be difficult for homeowners to determine what is causing the issue. For peace of mind, it is always best to ask a professional, they will be able to assure you that your system is safe and that it is operating correctly or remedy any issue that may have occurred.

DIY repairs on a home heating system are inadvisable for many reasons. Not only could you damage the system further, but without expert knowledge, it could be extremely dangerous to attempt any repairs yourself. Quite often DIY attempts to repair a malfunctioning furnace can cause even more problems, aside from the severe safety issues that can occur. This can lead to further expenses when you inevitably need to call in an HVAC company.



Although the cause of your failing furnace ignitor may be as simple as needing a replacement or dirty filters, there are several more serious issues that may be the culprit. It is never advisable to attempt repairs yourself, although knowing the probable cause can be helpful when calling to explain your issue to the HVAC company.

Calling in a professional as soon as a furnace issue has occurred is the best solution, for your safety and for your system. It is always good practice to have the contact details for a local HVAC company on hand when needed.


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If you are looking for trusted heating and cooling services in your area, call Hart Home Comfort today. We offer our customers a full line of HVAC services including heating and cooling replacements, tune-ups, repairs, and more! Our team of NATE certified technicians has the knowledge and experience to service your HVAC system correctly. All of our prices are highly competitive and we guarantee the work that we perform for you to ensure you satisfaction. Call Hart Home Comfort today for a free in-home estimate.

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