Posted by: Domago on January 30, 2003 at 20:33:05

Makes a thump when blower kicks on like a gate is closing between the air conc.coils and the warm air duct. Help!

Answer:
"Oilcanning" - a thump when the blower starts is usually a sheet of metal that is distorted inward and pops outward when the air pressure increases from the blower. You need to find that sheet by holding it from popping, so it doesn't make the noise when the fan starts and then fix the sheet with a brace, sometimes aluminum angle from the hardware supply and screws or pop rivets.