How Do I Know if My Flame Sensor Is Bad?

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The wintertime can be just the right time to catch up on some quality time indoors. You can choose to spend this time with loved ones, reading a book, or just lazing around enjoying the comfort of being warm.

One method to ensure that your home remains comfortable (the place to be) during the winter is by making sure that your furnace unit is running at the optimal level. A faulty or non-functional furnace system can cause significant inconvenience.

It can also cause health problems such as a rise in blood pressure and an increase in the common cold among household members. And if not treated immediately, they can lead to more serious health issues like heart attacks and pneumonia.

The increase in these health hazards is due to environmental factors surrounding your home, which is a result of the cold and damp weather in the winter.

And this is a result of the absence of a furnace unit or any other heating mechanism in your home.

Sometimes it can be due to the presence of a faulty furnace. Later in this article, you will have an answer to ‘“how do I know if my flame sensor is bad?”

A dirty or damaged flame sensor can severely affect the performance of your heat furnace unit. If your furnace unit stops and shuts down after it has been ignited or fails to generate heat, the flame sensor could be the cause.

So, How Do You Know if Your Flame Sensor Is Bad?

The flame sensor acts as a safety element to your furnace unit; it shuts down the furnace system when it cannot detect a flame; it does this to prevent a possible explosion.

A damaged or dirty flame sensor might still cause the furnace system to shut down, even if the flame is ignited and all the other components are operational.

Here Are Five Signs That the Flame Sensor in Your Furnace Unit Has Gone Bad

1. Yellow Burner Flames

How do I know that my flame sensor is bad? When it gives out yellow flames.

Open up your furnace or glance through the peephole to see the color of the flames firing up from the burner. If the flames are yellow, this indicates that the gas isn’t fully burning away, resulting from the carbon monoxide not being effectively vented out of the system.

Open your system up and gently clean the flame sensor; restart the furnace system to see if the flames return to the usual blue color. If the fire persists in the yellow shade, monitor the carbon monoxide levels in your home and contact an HVAC technician to assist with this problem.

2. High Utility Bills

How do I know that my fame sensor is bad? When your bills go up.

If your heating bill has been higher than usual, the first thing you should do is to check your air filters to ensure that they are clear. If they do not need to be replaced, the problem probably lies with the flame sensor.

The flame sensor in your furnace makes it difficult for your furnace to operate at its full potential; if that is the case, you might want to inspect the flame sensor and have it replaced or cleaned.

If the problem persists, consulting an HVAC technician would give you a deeper inspection of your furnace system.

3. Your Furnace Keeps Shutting Down

A properly functioning flame sensor will shut down the gas valve when it doesn’t detect a flame when the furnace should be firing.

In contrast, when the furnace has fired up and is steadily burning, a bad flame sensor will not be able to sense the heat and will shut down the furnace.

A simple way to test this is to check for your gas burners to light up, then leave for a few seconds; you could wait about.

The safety measure does not take long to kick in, and if your furnace keeps switching off, it could be a sign of a dirty or faulty flame sensor.

You might need to call a technician who can perform an HVAC repair procedure on your system unit. 

3. Dirty Flame Sensor

Like other regular equipment, a flame sensor is also prone to getting dirty over time. It is a sensitive sensor, so any dust or carbon buildup could cause it to malfunction.

This dust sticks onto the flame sensor preventing it from adequately performing its duties, causing it to malfunction and your furnace to shut down.

5. The Flame Sensor Is Cracked or Damaged

How do I know if my furnace flame sensor is bad? When it is cracked.

To determine if your flame sensor is cracked, you will need to open your furnace and inspect the flame sensor.

A bad flame sensor will have a crack on the outer porcelain part of the sensor; this is the part that is responsible for monitoring temperature changes and detecting the flame; if it is cracked, then it will be unable to perform this duty and will need to be replaced.

Cleaning the Flame Sensor

When your furnace has a faulty flame sensor, the cause can be a buildup of dust and debris on or around the flame sensor. And the solution to this could be as simple as cleaning the sensor.

When cleaning the sensor, first shut off the power to the furnace; it can be located in the burner assembly. It is a thin, usually bent metal rod placed in front of the furnace flame stream.

Use a screwdriver to remove the screw to access the sensor; when the sensor has been accessed, use fine sandpaper or something a bit abrasive like a dollar bill to wipe down the sensor.

Make sure to be gentle while wiping the sensor as it is sensitive. Once done cleaning the flame sensor, use a cloth or paper towel to wipe down the rod.

Conclusion

The flame sensor is your furnace’s most vital safety component and should be treated with utmost importance. It is also vital to differentiate between a dirty and a faulty or damaged flame sensor.

Although they can both tremendously affect your furnace’s performance, a dirty flame sensor can be amended much easier than a broken one.