If you reside in a cold-weather zone, your home most likely has a gas furnace for heating. Although the stove is an essential component of a building’s HVAC system, it is often overlooked until it fails. A faulty flame sensor is the most common cause of a defective gas furnace.
Although a flame sensor is a tiny component, it is an important safety element in gas furnaces. If the flame sensor fails, the gas furnace will not operate because the gas supply will be shut off. Hurliman, a reputable heating installation and repair company, recommends taking excellent care of your flame sensor and fixing it as soon as it exhibits difficulty.
You should check the flame sensor if your gas furnace isn’t working correctly. This post will walk you through the flame sensor troubleshooting process. Of course, if your flame sensor requires repair, you should see an expert.
What is the purpose of a flame sensor?
Before we go into how to diagnose a defective flame sensor, let’s first look at its function and operating principle. A flame sensor detects whether a flame is burning in the burner assembly.
If the gas supply is turned on, but the flame sensor does not detect a flame, the gas will be turned off automatically. The flame sensor’s function in avoiding a possible calamity is critical. Gas that exits the burner without a flame will build up in the air and may cause an explosion.
The sensor itself is a small metal rod that protrudes over the burner. When a flame ignites in the burner, an electric current is generated in the sensor. The wind is highly low-powered, measured in microamps. A control board reads the signals and chooses whether to maintain or turn off the gas supply.
When the sensor fails to detect a flame, the control board typically waits 10 seconds before shutting off the gas valve. After three failed tries, the system will be locked out, and you will be unable to start the furnace. You can reset the system and try it again. It is recommended that you consult an HVAC professional.
Typical issues with flame sensors
It is not uncommon for gas furnaces to experience issues with their flame sensors. There are various possible causes for your flame sensor to fail, but the most prevalent are:
1. It’s out of date.
A flame sensor, like any other gadget, wears down with time. It eventually grows too old and damaged to perform its function effectively. Most flame sensors provide optimal performance for up to five years before needing to be replaced. Inspect your gas furnace if it is more than five years old and still employs its original flame sensor.
2. Carbon accumulations
Carbon deposits on the sensor rod might obscure and prevent it from operating correctly. For example, when the burner has a flame, but the sensor cannot detect it due to carbon deposits, the system will continue to turn off the gas. An incorrect air-to-gas combination might cause substantial carbon deposits in the flames.
3. Debris and dirt
In addition to carbon deposits, everyday dirt and debris from the surroundings might accumulate on the flame sensor. Because most properties have gas furnaces situated in the attic or basement, this is a typical issue. The dirt particles pulled in from the surroundings eventually cover the sensor and prevent it from sensing fires.
What is the best way to troubleshoot a flame sensor?
Let us now look at how you may troubleshoot a flame sensor. To determine the cause of the malfunction, follow the procedures below:
1. Check the ignition.
Listen for the sound of the gas igniting as you switch on the gas furnace. The noise level should be compared to that of jet engines. Once the gas is lit, keep listening for a bit to see if it stays lit or goes out. In this manner, you’ll know if the burner assembly lacks a flame or if the flame sensor is misperceiving it.
2. Examine the thermostat batteries.
In the case of a power off, the thermostat in your gas furnace includes batteries that allow it to continue working using pre-programmed information. However, this might cause your furnace to fail, resulting in inaccurate flame sensor readings.
3. Examine the air filters
Airflow is another element that might interfere with the operation of the furnace’s burners. Over time, debris can accumulate in the air filters, clogging the air supply and impairing the furnace unit’s function. So first, examine the filters to check if they are blocked.
How to Repair a Flammable Sensor
When you’ve determined that your gas furnace has a malfunctioning flame sensor, it’s time to get it back up and running. What you can do is as follows:
1. Scrub the sensor
If the problem with the flame sensor is caused by dirt or carbon deposits, cleaning it may resolve the issue. Use an abrasive cleaning material to remove the residues carefully.
2. Make use of a multimeter
Use a multimeter to see if the problem is caused by a broken or worn-out flame sensor. In that scenario, you might need to engage a professional to replace it.
3. Speak with a professional
If you have tried all of the troubleshooting techniques and remedies and the problem continues, it’s time to call in a professional. A reputable gas furnace installation and repair firm should be able to resolve the issue promptly.
Finishing up
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Although faulty flame sensors are not rare, they can typically be avoided by keeping the equipment clean and well-maintained. However, if the flame sensor becomes too old, it may be necessary to replace it. If you require a flame sensor replacement, contact a reputable technician and get it completed.
