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What Does a Thermocouple Do on a Furnace?

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The parts of a furnace and how they function can seem mysterious. When the parts begin to malfunction, it can be hard to know what to do. 

What does a thermocouple do on a furnace, and how do you know when yours needs repair?

Our furnace repair team at S&L Air Conditioning and Heating is here to explain everything you need to know about furnace thermocouples. The more you know about your furnace, the easier it is to identify a problem and know when to call for furnace repair. 

The smartest thing to do when you have trouble with your furnace is to call S&L Air Conditioning and Heating. We are the #1 choice for all of Bowie’s furnace installation services, and we can determine the problem within your furnace and whether replacement is necessary or repair is possible. 

What Is a Thermocouple?

What does a thermocouple do on a furnace? The most important thing to know is that the thermocouple keeps you and your family safe. 

The thermocouple is part of your gas furnace’s safety system. It monitors the pilot light and extends to the gas valve. As long as the pilot light functions properly, the thermocouple stays open, keeping gas flowing into your furnace’s combustion chamber to warm your home.

Most of the time, the pilot light stays lit without issue, and the thermocouple stays open. Occasionally, the pilot light may go out. If the pilot light isn’t burning, that means gas is flowing into your home, which is very dangerous. 

The moment the thermocouple detects that the pilot light is not on, it shuts off the flow of gas, preventing the risk of explosion or carbon monoxide exposure. Without a thermocouple, gas would continue flowing into the furnace, where one spark could ignite it.

Is a Gas Furnace Dangerous?

Now that you know about the danger that comes with the pilot light going out, you may begin to wonder if an electric furnace is a safer option.

Modern gas furnaces include many safety measures. The thermocouple just happens to be one of those measures. 

Not only are gas furnaces safe, but they are much less expensive to operate than those with electronic ignition. Natural gas furnaces are safe for you and your family as long as you schedule routine maintenance with a qualified HVAC company.

If you are unsure about whether or not your gas furnace has all the required upgrades to be the most efficient option, a licensed HVAC technician can help you understand energy-efficient furnaces and guide you through the options for upgrading your unit.

Signs of Thermocouple Damage

As with all furnace problems, the best way to diagnose thermocouple damage is by scheduling an inspection with a professional HVAC technician. When the technician arrives, there are a couple of signs they can look for to determine the health of your thermocouple. 

Dirt Buildup

The inside of a furnace can get dirty, especially during the warmer months when it is not in use. While some of this dirt, dust, and debris burns off the first time you turn on the furnace each year, too much buildup on the thermocouple could cause a problem. 

Loose Wires

Over time, it’s natural for parts to shake loose within your furnace. If loose wires are causing your thermocouple trouble, an HVAC technician will be able to perform repair and recalibration. 

If the HVAC technician determines the thermocouple is no longer viable and not a candidate for repair, a total replacement will be necessary.

When to Replace Your Thermocouple 

A well-maintained furnace could last at least 20 years. Even with regular maintenance, a thermocouple will not last as long. The thermocouple will need replacement at least once throughout the life of your furnace. 

The good news is that it’s easy to determine if you need a new thermocouple, and a professional can easily replace it. 

When you stay diligent about furnace maintenance and have a trained HVAC technician inspect your unit annually, it is possible to repair a malfunctioning thermocouple before you even notice there is a problem.

Contact Us for Expert Furnace Repair and Replacement

What does a thermocouple do on a furnace? Now you know: It keeps you and your family safe in the event of pilot light failure.

Don’t let a faulty thermocouple leave you in the cold. Call 301-923-4571 to schedule an appointment with the best team in Bowie for furnace repair. Our experienced technicians at S&L Air Conditioning and Heating in Bowie, MD, will get your furnace back in top-notch shape.

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