Furnace flame sensors: value, how they work, and when to restore

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A flame sensor is likely one of the most essential security options of your furnace. This part is chargeable for making certain that your furnace doesn’t create a harmful gasoline leak or explosion.

By understanding why the furnace flame sensor is essential to the unit’s operation, you’ll be higher ready to acknowledge when a flame sensor is dangerous. Our information will stroll you thru cleansing the sensor and furnace flame sensor alternative.

What’s a flame sensor?

The flame sensor is a security part of a furnace situated on the inside of the burner meeting. It screens and verifies whether or not a flame is burning contained in the unit.

If the sensor doesn’t detect an lively flame, then it would shut the furnace off to keep away from a possible gasoline leak. The furnace flame sensor helps forestall explosions that would happen if gasoline had been allowed to proceed to move into the house in addition to carbon monoxide poisoning of these inside the house.

The Facilities for Illness Management and Prevention report that no less than 430 folks die within the U.S. from unintentional carbon monoxide poisoning annually and a few 50,000 go to the emergency room due to the gasoline. Whereas residence furnaces are chargeable for solely a small share of those instances, it’s a worthwhile reminder to put in a carbon monoxide detector on every stage of your property.

Flame sensor vs. thermocouple

A flame sensor and thermocouple are also known as the identical or interchangeable components, however that’s not the case. Whereas they each function a security function on the furnace, you would wish to know which you could have so as to change or restore the part.

A thermocouple is commonly discovered on older mannequin gasoline furnaces with a standing pilot. It has a small flame that burns repeatedly, holding the highest of the thermocouple at a excessive temperature. If the flame goes out and the tip of the thermocouple cools, it would robotically shut off the furnace’s gasoline valve.

Flame sensors are utilized in fashionable furnaces that function through an digital ignition moderately than a standing pilot mild. These fashions use digital igniters to mild the gasoline. As talked about above, the flame sensors make sure the burners are working correctly and have ignited the gasoline. If the sensor detects that the burner has failed, it would flip off the gasoline.

Furnace flame sensor location

When attempting to find out easy methods to discover a flame sensor, you’ll need to take away the furnace entry cowl to start. Relying on the mannequin of your furnace, you could have to take away screws or bolts to launch the entry cowl.

The sensor is situated simply outdoors the burner meeting and appears like a small rod with porcelain surrounding the top that connects to the burner. Some furnace flame sensors are straight whereas others bend at a 45-degree or 90-degree angle. The sensor leads into the hearth chamber the place the flame burns.

Indicators of a nasty flame sensor

As with all different part in your heating and cooling system, the flame sensor can go dangerous. In case your furnace stops working correctly, search for warning indicators that your flame sensor has failed:

• Furnace burners activate however exit after just a few seconds
• Soot and different particles is masking the top of the sensor (cleansing the flame sensor could repair this situation moderately than a flame sensor alternative)
• Tip of flame sensor is black
• Porcelain/sensor casing is cracked

If a flame sensor alternative is important, it’s a low-cost repair which you could possible deal with your self should you really feel snug working with the unit. Most furnace flame sensors value lower than $20, however should you decide to have an expert HVAC technician make the restore, you possibly can anticipate to pay between $75 and $250.

Flame sensor lifespan

When you’ve simply changed the sensor or had a brand new furnace put in, you possibly can anticipate the flame sensor to final for about 5 years. The typical lifespan of a furnace is 15 to 30 years, so you possibly can anticipate a flame sensor alternative a few times over the course of your homeownership.

To increase the lifespan of the sensor, seasonal furnace upkeep and cleansing the flame sensor is important. Even when the furnace appears to be working easily, cleansing the sensor annually can forestall you from calling for emergency heating companies in the course of winter.

Furnace flame sensor cleansing

Earlier than you start the flame sensor cleansing course of, flip the gasoline and electrical energy off to the unit. The valve deal with on the gasoline pipe will can help you cease the gasoline move and turning off the furnace breaker at your electrical field will guarantee all energy is shut down.

If the furnace has been operating, wait no less than half-hour earlier than trying these steps:

• Find the flame sensor (check with the furnace flame sensor location portion above)
• Take away the furnace entry cowl, which can contain releasing screws or bolts
• Unfasten/unscrew the flame sensor from the burner meeting
• Disconnect the wiring that results in the sensor and management field
• Loosen the screws and take away the flame sensor
• Use an emery material to softly take away soot and different particles from the sensor
• Reattach the sensor
• Reconnect the wiring to the sensor and management field
• Safe the flame sensor to the burner meeting
• Reattach the furnace cowl entry

Check the furnace to see if cleansing the flame sensor was the answer you wanted. If the unit activates and off correctly, a flame sensor alternative might not be crucial.

Change furnace flame sensor

In the course of the sensor cleansing course of, should you uncover the tip of the sensor is black or the part is misshapen or damaged in any means, change moderately than restore the half. Comply with the flame sensor cleansing steps, however set up the brand new sensor as a substitute of cleansing the previous one.

Your furnace will solely function with a sure sort of flame sensor. Make sure the part you buy is appropriate along with your unit. Test the proprietor’s handbook for steering on the kind of sensor you want.

If working with a furnace or dealing with the gasoline line just isn’t inside your DIY consolation stage, take the secure route and name an HVAC skilled. A furnace specialist will take a look at the flame sensor and change it if wanted.

To keep away from being caught in a scenario the place furnace service is required instantly, schedule routine inspections. Seasonal upkeep can help your unit in working correctly whenever you want it most and increasing the lifespan of the furnace. Discover our prime furnace manufacturers if it’s time to interchange your unit.