Keeping Your AC System Cleaner

A Bad Door Safety Switch Should Be Replaced So Your Furnace Isn't A Safety Hazard

by Yolanda White

If you have a gas furnace, it probably has a door safety switch. This switch is an important safety feature that keeps you safe from toxic fumes. The switch may never cause any problems, but if it does, the switch should be checked by a furnace repair technician and replaced if necessary. Here's why the switch is important and a look at how it's replaced.

The Purpose Of A Furnace Door Safety Switch

The safety switch controls power to your furnace. The door panel on the furnace has to be closed for the switch to be on and for the switch to allow power for the furnace to run. When the door is removed, the switch flips off and the power to the furnace is cut off.

This is an important safety feature because if the furnace keeps running after the door is removed, the blower can suck exhaust fumes into the air handler instead of letting the fumes escape through the flue. Once that happens, the fumes circulate through your home rather than escape outdoors.

You should never run your furnace with the door open, and it isn't possible to do so if the door safety switch is working properly.

How A Furnace Repair Technician Replaces The Switch

The switch is hidden behind the door of a furnace, so it may be difficult to know when the switch is damaged or broken off. However, if that happens, the repair technician can tell just by looking at the switch once the door is open. If there's an electrical problem, the switch has to be pulled out and checked with a meter. This helps the technician determine if the switch is bad or if a connection was loose or if the wiring is bad.

The door has to be removed to access the switch. Switches have different shapes, but the back looks similar to a plug with prongs and the front has a plunger or switch that can be depressed. The wires have to be removed from the prongs and then the switch can be pulled out, tested, and replaced with a new switch if necessary.

Once the new switch is installed, the furnace repair technician replaces the furnace door and restores power. Then the switch can be tested by removing the door and checking that the furnace stops operating.

A safety switch is an inexpensive part to have replaced, and since it's an important safety feature, you don't want to put off having the repair done. It's even possible to have a switch put on an old furnace that doesn't already have one so your family is safer in the winter when the furnace is running.

For more information on safety switches, reach out to a furnace repair service near you.