I belong to a little brick bungalow in the midwest US built in 1954. Original forced-air (galvanized ductwork) heating, 2-yr-old Heil 80% furnace.
Lying in bed, very quiet, furnace begins heat cycle. About 15 seconds after the burners fire, I hear a big POP. Very consistently. Every night.
I know that the furnace heat makes the sheet metal expand, and a certain amount of noise (creaks, squeaks, etc) is to be expected, but this one sounds too loud.
Walked the length of the ductwork, tapped each joint with a mallet, inspected everything. No apparent problem.
Still I get the big POP.
Anything with 50-year-old galvanized ductwork that I should be looking for?
Thx, Peetie