The flame rollout switch is an essential furnace safety feature that makes sure the area around the burner doesn't become a hazard for a fire or carbon monoxide leak. If the switch senses either of these possibilities, the unit will turn off. Or a broken switch can turn off your unit even if one of those dangers isn't present.

If you suspect a problem with the flame rollout switch, first follow the instructions in your owner's manual for resetting the switch and then test the unit. If the problem persists, you can install a new rollout switch and see if this fixes the problem.

Note that the presence of gas, electricity, and the possibility of a gas leak make this repair project best left to those who have furnace repair experience. Ensure that you have a carbon monoxide monitor present so you will know if something does go wrong. Otherwise, call in a professional heating services tech to perform the job.

What You Need:

•    Screwdriver

•    New flame rollout switch

Step 1: Remove the Old Rollout Switch

Shut off the power to the furnace at either the shut-off switch or the breaker box. Turn off the gas supply using the shut-off valve on the supply line leading to the furnace.

Using a flathead screwdriver, remove the screws holding the upper access panel in place. Remove the panel and set the panel and its fasteners aside.

Locate the rollout switch within the top access area. Unhook the wires attached to the bottom of the switch by pulling firmly. Use a wrench to remove the mounting screws holding the switch onto the furnace burnout box. Pull the switch out of its housing and then out of the furnace.

Step 2: Install the New Rollout Switch

Take the new rollout switch out of its packaging. Align the new switch into the vacated slot in the burnout box using the mounting screw holes as a guide. Insert the mounting screws and tighten into place with a screwdriver to secure. Hook the wires up to the new switch by pressing each wire firmly into place.

Slide the top of the access panel door into position and then the rest should quickly follow. Insert and tighten the fasteners. Turn on the electricity and gas, then conduct a test run to see if the furnace is operating properly. If the furnace is still having issues, you should contact a heating services company, like Staley Mechanicals, for assistance.