recently in the middle of the night ive been hearing these loud bangs that would wake me up in a way that would keep me up, scary stuff. royal heating came over diagnosed the problem as to much neg pressure in the system, what ever that is right lol well they explained it to me, its common reasons for happening ect. they made a few tweaks to my system - played with settings, added foil tape, that kind of stuff, over 2 weeks now and no more gun shot sounds in the middle of the night. i found them to be:
knowledgable
personable
and reasonable people
I would recommend these guys to my own mother in a heart beat