Goodman furnace making flapping noise in defrost mode

General topics about all things heating, ventilation, air conditioning and refrigeration.

Goodman furnace making flapping noise in defrost mode

Postby roger2389 » Sat Dec 03, 2011 11:12 am

When my furnace is in defrost mode (fan not turning outside) I hear a loud noise that sounds like there is something flapping underneath the house. I have been under the house and checked all the duct work and found nothing loose. 2 different companies have come out to check it and of course it want make the noise when they are here. Odd thing is it does not make the noise everyday just usually early in the morning when I am trying to sleep. Anyone have ANY ideas on what could be causing this noise?
roger2389
Minimal
 
Posts: 1
Joined: Sat Dec 03, 2011 11:10 am

- Goodman furnace making flapping noise in defrost mode

Postby Freon » Sat Dec 03, 2011 4:04 pm

When your heat pump is in defrost mode, does the indoor air circulate in the duct work? Check the copper tubing and see if it runs under the house where the noise seems to come from. If it does, next time you think there will be noise, put your hand on each tube CAREFULLY and SLOWLY. Feel for vibrations and possible pulsing... a burst of bubbles flowing through the tubing. Check the suspension of the tubing.

If the indoor air does continue to flow then usually the furnace will come on. Possibly the hot air from the furnace causes duct expansion (metal ducting) and you hear that noise.
Freon
Most Valued Contributor
 
Posts: 691
Joined: Sat Jun 18, 2011 11:26 am

- Goodman furnace making flapping noise in defrost mode

Postby MTI STUDENT » Sun Dec 04, 2011 1:38 am

are you using a timed thermostat with a low night setting?
MTI STUDENT
Most Valued Contributor
 
Posts: 27
Joined: Sun Dec 04, 2011 1:27 am

- Goodman furnace making flapping noise in defrost mode

Postby heatseeker » Mon Dec 05, 2011 9:45 am

Maybe there is a wild animal under there that gets scared when it goes into defrost. Second guess liquid line pulsating.
heatseeker
Most Valued Contributor
 
Posts: 542
Joined: Wed Jul 06, 2011 9:10 am

- Goodman furnace making flapping noise in defrost mode

Postby heatseeker » Mon Dec 05, 2011 9:47 am

Third guess there is a duck caught in the duct.
heatseeker
Most Valued Contributor
 
Posts: 542
Joined: Wed Jul 06, 2011 9:10 am


Return to HVAC General Forum

cron