what is emergency switch for (furnace, room, detector, gas)

[mimosa]

Outside our boiler room is a switch on the wall that says "gas boiler emergency on or off. We have it on but don't know why. It has also been in the off position and everiything seemed ok. which position should it be in and why?

[rubytue]

We have one for our oil burner. Hadn't really thought about when to switch it off, other than in a fire or if the CO detector goes off.

[JBrown]

The switch when placed in the OFF position should immediatly shut the furnace down, wether it be oil or gas fired. With the furnace running flip the switch to the off position. If the furnance keeps running the switch wiring is faulty. If that's so, get it fixed. The switch is supposed to be placed not on the furnance itself but at an easy to get to place...as you enter the furnace area...not so that you have to go around or approach the furnace. it's function is to immediatly shut off fuel and electrical power so that in the event of a fire,flue blockage etc the emergency folks don't have to battle a runaway system etc.

[Tony22]

I am going on vacation soon . Is it neccessary to turn off the boiler by hitting the emergency switch?