How to Clean a Hot Surface Igniter

A hot surface igniter acts like light bulb filaments in the sense that electrical currents pass into it. Instead of generating light though, the igniter’s goal is to generate enough heat to ignite gas that, in turn, heats the air in a furnace. If the mechanisms inside the furnace get too dirty, however, they can cause a hot surface igniter to fail. Unfortunately, simply cleaning these parts is more difficult than it seems because the ignition side of a hot surface igniter should never be touched. Instead, it is primarily the peripheral parts of the hot surface igniter that must be cleaned. Follow the steps below to learn how.

Step 1 – Turn off the Gas and Electricity

To be safe, whenever doing work on a stove, furnace, or other gas fueled device, it is wise to shut off the gas. The shut-off is usually a ball valve located before the first appliance after the gas line enters the house. In this case, because the hot surface igniter is hardwired into the house’s electrical system, it is smart to turn off the electricity to the house as well by flipping the main circuit breaker off.

Step 2 – Remove the Hot Surface Igniter

Using a socket wrench or screwdriver (depending on how it is attached), remove the panel from the side of the furnace and locate the hot surface igniter. The igniter will be attached to some electrical wires that are easily unplugged. A socket wrench or screwdriver will be needed again to remove the igniter itself. Once the igniter has been removed, DO NOT touch the glass-like side of the igniter. This part of the device is extremely fragile, so much so, that even the oil from one’s hands can ruin it. Just inspect the glass-like side for hairline cracks and use a can of compressed air to blow any dust off of it. If there is a crack, there is no way to fix it, and the igniter will have to be replaced.

Step 3 – Locate the Filter

The filter of the furnace may also be dirty, which would cause the furnace to heat up more than usual, forcing the safety features to shut off power to the hot surface igniter. Air filters simply slide out, and the replacements slide right back in. This is an easy process and an important part of good furnace maintenance. Change the air filters regularly.

Step 4 – Clean the Electrical Housing of the Furnace

Before replacing the hot surface igniter, use a shop vac or compressed air to remove and dust or dirt that may have built up in the electrical compartment where the hot surface igniter is housed. Once the area is clean, replace the igniter and reattach the side panel.