In Hot Water

I have a new hot water heater.
The guys arrived early and finished installing it about fifteen minutes ago. They were here for almost three hours.
Now, as I sit here typing these words, I can hear the new hot water heater boiling and burbling in its new space.
Honestly? It sounds a bit sinister and is making me wonder: what sort of sounds does a hot water heater make before it explodes?
Okay, now I'm totally getting paranoid.
So, I think I'm off to the movies. I figure, if the house isn't blown up by the time I come back, everything'll be copacetic.
Still alive and being a bit silly. - G.