Home>Discussions>INSULATION & HVAC>Cranking noise (clunks) when air heater comes on.
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mpathak
Cranking noise (clunks) when air heater comes on.

We recently moved into a 31 yr old ranch house and this problem is driving us crazy.

Every time the heater comes on (and now a days it is frequent) we get these clunks in our master bedroom near the air outlet. I also found it is there at various other spots as well, throughout the house. They continue to come even after the heater is off (as long as 4-5 min. after it is stopped)

I went to the basement (70 % finished) to see where is coming from and I can see it is coming from the end of the big pipe that is going into the room floor.

How can I dampen or eliminate this noise?? Is this a common occurrence?

Your help is much appreciated - Thanks in advance.

A. Spruce
Re: Cranking noise (clunks) when air heater comes on.

Most likely it is the expansion and contraction of the ductwork against framing members.

mpathak
Re: Cranking noise (clunks) when air heater comes on.

Thanks for your reply.

Any remedy on reducing or eliminating it?

Thanks again,

A. Spruce
Re: Cranking noise (clunks) when air heater comes on.

Isolation is the only remedy. Any place you see framing touching the duct, force a little fiberglass insulation in or enlarge the hole. You don't need much, you just need to NOT have contact with the duct.

Blue RidgeParkway
Re: Cranking noise (clunks) when air heater comes on.
mpathak wrote:

We recently moved into a 31 yr old ranch house and this problem is driving us crazy.

Every time the heater comes on (and now a days it is frequent) we get these clunks in our master bedroom near the air outlet. I also found it is there at various other spots as well, throughout the house. They continue to come even after the heater is off (as long as 4-5 min. after it is stopped)

I went to the basement (70 % finished) to see where is coming from and I can see it is coming from the end of the big pipe that is going into the room floor.

How can I dampen or eliminate this noise?? Is this a common occurrence?

Your help is much appreciated - Thanks in advance.

Good advice here:

How to Quiet a Noisy Forced-Air System: http://www.thisoldhouse.com/toh/video/0,,20047185,00.html

Quieting Noisy Ducts: http://www.thisoldhouse.com/toh/asktoh/question/0,,1131823,00.html

mpathak
Re: Cranking noise (clunks) when air heater comes on.

Thank you again A. Spruce and Blue Ridgeparkway..This is great advice..Next stop Lowes - Fiberglass insulation and the rubber pads..

Thanks you!

Blue RidgeParkway
Re: Cranking noise (clunks) when air heater comes on.

you are welcome and good luck.

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