I had the utility company serviceman come out to do a safety check on a wall gas heater (which is 20+ years of age). He said it was fine. No replacement needed at this time. The problem is that when the heater goes on, the unit will make a LOUD pop sound and the heater will sound like an engine afterburner. I'd like to know what causes that sound, if there's a fire or carbon monoxide risk involved here and if it would be a good idea to just replace the whole unit.
What concerns me though is why the pilot light went out.