How To Clean Furnace Flame Sensor

First off, before you even try to clean your furnace’s flame sensor you’ll want to make sure that the power is completely off. Turn the furnace off from its main power switch so you can be certain that it won’t start inadvertently. You may also want or need to shut the furnace off by throwing a circuit breaker in order to be completely certain that it won’t start.

As soon as you have the system powered off, you’ll want to remove the plate that’s in front of where the flame sensor is installed. On many models, this will slide right off, though there’s a chance that you might need to unscrew a few fasteners to get inside. Chances are that the flame sensor itself is held in place by one or more ¼” hex head bolts. You can use an Allen wrench or a hex key to open these up and pull the flame sensor itself out.

Cleaning Off The Sensor Body

Detach any wires that are currently plugged into the flame sensor and take it completely out of the inside of the furnace. Use a paper towel or a completely lint-free cloth to remove any excess dirt from the sensor rod.

If there’s a lot of buildup, then you can use an extremely delicate piece of light grit sandpaper to remove the buildup. Any use of sandpaper should be gentle and should never touch any other component attached to your furnace. Use paper towels or lint-free cleaning cloths to remove any dust that you create in the process.

Take a moment to turn your attention back to the inside of the furnace. Use a shop towel to clean out any debris or dirt that’s made its way in there as well. As soon as everything is clean, hook any wires that you removed from the sensor back up to their jacks and then slide the sensor back inside of the furnace.

Once it’s secured, replace the hex screws to hold it in place. While you want to make sure that they’re tight, you don’t want to over-tighten them because it’s very easy to snap the little holders that these fit into.

Carefully slide the original panel back into place and close up the furnace. Assuming that everything went well, the furnace flame sensor should work like normal again. If there were any performance-related problems to begin with, then this may very well have solved them. Once it’s in place, the sensor will more than likely not require cleaning again for some time.

Troubleshooting The Flame Sensor

Check to make sure that you reconnect everything properly if the sensor doesn’t switch on correctly once you’re finished. Use the same degree of caution when disconnecting the system in order to ensure that you don’t do any damage to it.

Follow More Step-By-Step Flame Sensor Instructions From Furnace Part Source

Furnace Part Source has replacement parts in stock if anything seems wrong with it, but these often just need a good cleaning and reassembly to work well again.

Those who end up needing a new furnace flame sensor for whatever reason should feel free to contact our team online. They’d be glad to help you get the parts you need to restore your furnace.