Quadrafire DVI 32 Noise

[BWPMT]

I have a Quadrafire DVI 32 natural gas fireplace. It works just fine, but when it fires it makes a loud metal clanging sound, as if a damper or spring loaded valve is opening. It does the same after cooling down. How do I eliminate this noise?

 

[Heatsource]

If it is from metal expansion as the unit heats and cools there may not be much you can do.
if you could id the part of the unit or heat exchanger causing the problem then some type of action could be possible....

 

[DAKSY]

Check with your local HnG/QF dealer. There were some problems with "Oil Canning" of metal insert shells about 6 - 8 years ago & the engineers came up with an expansion kit to mitigate this problem. Essentially, the kit consists of 2 or 3, (1/2") steel angles that get Zip Screwed to the rear of the box, which is the largest surface. That surface can't expand past the corner joints, so it'll make a loud "BANG" as it "oil cans." That additional bracing seemed to prevent the expansion/contraction...

 

[BWPMT]

thanks for the replies! I does sound somewhat like the "oil canning" description. I just don't know why the unit has not always had this problem. Last year this happened twice. I giggled the "spring loaded" bolt which sticks out of the small box connected to the exhaust vent, and the sound stopped. I rebuilt the fireplace surround this year, and moved the unit around a little, and now the sound is back. Moving the "spring loaded" bolt doesn't seem to help. There is a small screw sticking out of the exhaust vent tube that is very loose, almost to the point of falling out. I can't find a parts list or mechanical diagram for this unit to determine the purpose for this screw.