Vent hood -- placement of backdraft damper

attofaradApril 29, 2012

I'm installing a Broan hood with a rooftop blower. The blower has a backdraft damper on its output, but Broan still indicates in the spec/instructions that one should be added inline.

The most convenient place for the damper would be immediately attached to the hood. For one thing, I could verify operation (and change spring if necessary, adjust, lube) by removing the hood baffles for direct access. The only reason I can think of for not putting it there would be if the flappers would result in more air turbulence noise if placed on the hood exit than if placed a bit further up the path.

Any experience with this?

Thank you for reporting this comment. Undo
Fortinbras

Bump.

We just installed a custom hood with Broan PIK 45 and EB 15 external 1500 cfm blower. There clearly is still a bit of a draft. I'm going to talk to our contractor / HVAC guys tomorrow about installing this back-draft gizmo.

Any input or comments appreciated.

Will post updates.

    Bookmark   April 29, 2012 at 7:30PM
Thank you for reporting this comment. Undo
kaseki

attofarad:

My hood has a damper just above it supplemental to the one on the output side of the roof fan. I don't think the hood damper adds significant noise, but a comparison test would be extremely inconvenient.

In any case, differential pressures due to wind gusts will cause some damper opening, so a pair of dampers provides additional resistance to air infiltration down the duct.

kas

    Bookmark   April 29, 2012 at 9:15PM
Thank you for reporting this comment. Undo
attofarad

Thanks Kas, I will just add it right to the hood port.

Gary

    Bookmark   April 30, 2012 at 4:17AM
Sign Up to comment
More Discussions
My GC thinks I need 1000 cfm and I think he's crazy
So I actually don't think he's crazy and he's right...
crl_
Wolf porcelain chipping on new ovens
Argggggg!!!! New wolf E series ovens, purchased and...
jackson2348
Bosch Benchmark Policy....
I live in the FL Keys, and we have very few options...
cudjoegal
New Bertazzoni Induction Range?
I just saw a press release from Bertazzoni about a...
anyajg
48 INCH DUAL FUEL RANGE OR LP GAS
Planning to purchase the 48 inch- dilemma: any inputs...
hkwan
© 2015 Houzz Inc. Houzz® The new way to design your home™