Help me diagnose a problem

Alright so this past weekend I was sick and sent my two guys out to wash trucks and of course something has to break while I’m down for the count. They said they turned around and saw billows of smoke coming out of one of the units and they ran over and turned it off. They then turned off the burner and ran it and saw this leaking.

They said a bunch of black stuff came pouring out of here

And they said it smoked for like 30 minutes after this happened. My best guess is a burst disc because the coil overheated but I don’t know where that is or how to replace it. Would appreciate some help here.


Specs, make and model, and what is coming out of what?

Looks like you popped the coil