Possible Signs of Furnace Flame Sensor Issues

signs furnace flame sensor issues

There are a few components that play an important role in the operations of any HVAC system, and the realm of sensors cannot be ignored. There are a couple different sensors that will require immediate attention if they’re experiencing problems, and a great example within your furnace as we hit the winter months is known as the flame sensor.

At Accurate Air, we’re here to help clients around Tempe and Scottsdale with all their AC and furnace repair, installation and other needs, including for important components like these. What is a flame sensor in the furnace, why is it important, and what are some signs that your flame sensor might be having problems and require some professional attention? Here are some basics.

What is a Furnace Flame Sensor?

For those just hearing the term for the first time, the furnace flame sensor is a sensor that’s present within your furnace at all times, designed to detect when your flames are actually lit and producing heat. More specifically, the sensor will sense various aspects of the flame itself, including its color and temperature.

The sensor’s main job is to ensure that flame is only present when gas is in the chamber as part of an active heating cycle. If the flame disappears for any reason, such as a malfunction or a case where gas isn’t present when it should be, the sensor will detect this and shut down the furnace to prevent dangerous situations.

Why Flame Sensors Are Vital

If you think about the potential dangers that could take place if a furnace were to continue running without an active flame, it’s easy to understand why this sensor is so vital. Not only could you be paying for heat you’re not receiving, you may also be at risk of gas leaks or even fires in certain situations.

But with a working flame sensor, this risk is mitigated. As soon as the sensor detects that the flame has gone out or isn’t present when it should be, it will send an immediate signal to shut off the furnace and prevent any potential issues.

A malfunctioning flame sensor may give off a few telltale signs of problems – which we’ll go over in our subsequent sections.

Constant Clicking Sound

Particularly as your system is attempting to turn on and begin heating, one of the most common signs of a flame sensor issue is a constant clicking sound. This sound comes from the igniter in the system clicking as it attempts to turn on the flame – it’s okay if one or two clicks happen here on occasion.

However, if you hear a constant clicking pattern that goes on and on without any flame ever starting, this could be due to a malfunctioning flame sensor.

Yellow Flame

When it’s working properly, the flame inside your gas furnace should always be a bright blue color. If you notice it’s turned yellow or orange instead, this is a sign of an incomplete combustion process that may be due to the flame sensor not functioning as it should.

This is an important sign to report to our furnace repair services ASAP if you notice it.

Poor Exhaust Smells

In other cases, a malfunctioning flame sensor may cause the furnace to produce strange smells when it’s running. This could include gassy or burning odors, both of which are based on the fuel source in your system and how it’s being burned.

If you notice any such smells while your furnace is running, this could again be due to a flame sensor issue – make sure to contact our team if this happens.

Significant Rust Around Igniter

Another potential sign of a flame sensor issue: Signs of rust or corrosion around your furnace’s igniter. This may be due to an extended period without the flame turning on, which could mean the flame sensor is not functioning and allowing for excess water vapor to build up in the system.

While existing rust cannot be removed, the source issue will require attention from one of our techs.

Furnace Short-Cycling

Finally, a flame sensor problem may lead to what’s known as short-cycling – a situation where your furnace turns on and off rapidly over a short period of time. This can cause significant wear and tear on the system, often leading to multiple component issues at once.

If you notice any of the above signs or have other concerns about your furnace’s flame sensor, don’t hesitate to contact our team at Accurate Air for assistance and further guidance today. We assist clients around Tempe, Scottsdale and nearby areas with all their furnace repair needs.

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