"Clang" before shutoff

[tim s]

I have an Intertherm (#M1MB 070A BW) furnace. Recently I have noticed a "clanging" or "banging" noise at the end of a heating cycle just a few seconds before the blower shuts down. I would say it sounds like a small metal door slamming shut. It only recently started doing this, I noticed it right away. The furnace was new with the house in 2003. It appears to be functioning normally other than that. I do not know if it will do the same thing at the end of an A/C cycle, I have not had the A/C on yet this year. I searched this forum, but didn't find any similar problems. Any ideas?

[Robert]

Turn on a/c and see if it does it after a short cycle.

Remove blower assembly and inspect motor mounts, bands or brackets.


Inspect wheel for looseness on shaft or free spinning.



Thanks,
Robert