I am living in a new apartment, ie newly-built for less than 2 years.
The bathroom uses a gas heater, which I think is "room-sealed" (as in that I cannot see the flame or any insides, only the switch).
All along, the gas heater has always made a "thud" sound when I turn the gas on, and the moment I turn on the water. Recently, the "thud" sound has become an tiny explosive "bang" (something like a neighbour banging a door very hard).
Should I be worried? I have not smelt any gas, and the water still heats up normally.