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Douglas, HVAC Technician
Category: HVAC
Satisfied Customers: 3089
Experience:  Manufacture Rep for Major Brand, Technical Trainer, NATE
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Our gas furnace has started to clunk loudly when it shuts off.

Customer Question

Our gas furnace has started to clunk loudly when it shuts off. It is about 3 years old and was inspected in August. What could be causing the clunk?
Submitted: 7 years ago.
Category: HVAC
Expert:  Bill replied 7 years ago.
on somthing this new, the only thing i can think of is the ductwork expanding after the fan shuts down, try cleaning or replacing your air filter.

Edited by Bill on 1/7/2010 at 5:07 AM EST
Customer: replied 7 years ago.
The furnace and all the ducts were cleaned late in August and the filter was just changed. That's not it.
Expert:  Bill replied 7 years ago.
ok, ill opt out so others may help.
Expert:  Douglas replied 7 years ago.
Does the clunk happen when the burners shut down or when the blower shuts down?