Then people complain of a smell of burning, and hope the house is not on fire, and you ease their mind by explaining to them that it is probably only your boots.

Complicated internal arrangements are worked by a key.

If you put on too much fuel, and do not work this key properly, the thing explodes.

And if you do not put on any coal at all and the fire goes out suddenly, then likewise it explodes.

That is the only way it knows of calling attention to itself.