Furnace door blew off!

[Plumber69]

A guy called me and told me he heard a boom and his furnace door blew off. I told him to shut it down. What usually causes this. Plugged burner tubes?

 

[Plumber69]

Im thinking everything in the furnace has to get checked. He says its 25 years old

 

[Sponsor]

 

[Stuff]

Get some pictures. You need to do an autopsy. Door and chassis probably bent or torn. Time for a new furnace.

 

[Dana]

That sort of "symptom" is usually traced to a small gas leak, creating an explosive mixture inside the cabinet, subsequently set off during an ignition phase when the furnace is starting.

Plugged burner tubes can create soot deposits on the heat exchangers and poor combustion efficiency, high carbon monoxide emissions and other fun stuff, but usually not explosions.

 

[Bigmesa]

Dana is on point. If I had to guess it would be that the gas valve is not seating all the way when the unit shuts off and causing a very dangerous situation. An wasy test would be shut the power off to the furnace and take a lighter to the orifices that feed the burners. If you light a flame you've got a bad gas valve.

 

[WorthFlorida]

Dana is on point. If I had to guess it would be that the gas valve is not seating all the way when the unit shuts off and causing a very dangerous situation. An wasy test would be shut the power off to the furnace and take a lighter to the orifices that feed the burners. If you light a flame you've got a bad gas valve.

Not a good way to test for a gas leak. With enough gas accumulated in the burner area or flue, it could blow up in your face. Never ever use a flame to test for leaks.

 

[Bigmesa]

Not a good way to test for a gas leak. With enough gas accumulated in the burner area or flue, it could blow up in your face. Never ever use a flame to test for leaks.

Obviously we are taking about with the cover off and aired out. If you smell a strong gas leak then soap would find it faster. But a small leak of a gas valve would not be dangerous to test this way, been doing it for a living for over 20 years and never had an incident. Again common sense goes a long way here, this would be trying to find a leak the equivelant of a pilot light or smaller.

 

[WorthFlorida]

You always must assume you're dealing with a DIYer and can take your suggestion differently. Dale Earnhardt refused to use the HANS restraint in his cars because his head never popped out of the socket before, well guess what killed him.