Darn "Flapper" won't shut up!

OldPete · Oct 29, 2006

Ok... on a bathroom vent (fan vent, not DWV) there is a "flapper" built into the exhaust vent. It is meant to keep closed when air blows into it from outside and open when air blows into it from inside.

Because of high winds, the dam thing is constantly heard banging away... I have triple checked that it IS installed correctly.

What gives?

Thanks,

Pete

Verdeboy · Oct 29, 2006

If it's installed right, then there must be some wierd pressure changes occurring inside the attic or wherever this flapper vent is located. Once the flapper is partially open from the inside, the wind has something to grab onto and it opens it further, then slams it shut. Maybe you can remove the flapper gizmo and install one of those louvered vent covers--like they use for dryer vents.

Sponsor · 2022-01-29T12:20:58-0800

OldPete · Oct 30, 2006

Verdeboy said:
If it's installed right, then there must be some wierd pressure changes occurring inside the attic or wherever this flapper vent is located. Once the flapper is partially open from the inside, the wind has something to grab onto and it opens it further, then slams it shut. Maybe you can remove the flapper gizmo and install one of those louvered vent covers--like they use for dryer vents.

It is 100% installed right. Now here's where it gets even more silly.

On one application there *is* the louvered type that flip up and down when air is blown toward the outside, on the other one there isn't that type. Both make the banging.

I'm going to have at it and see about just removing the thing all together. Both have screens on the outside to avoid issues with bugs, etc.

Thanks,
Pete

OldPete · Oct 30, 2006

Got the answer and the solution.

Called NuTone... it turns out that even if the unit *is* installed correctly the reason that the flapper bangs away is caused by the pressure inside the house. Let me explain. In an older and not-so-well-insulated house the presure inside the house causes the flapper to flip open and closed. The banging noise.

The tech at Nutone said to try a small strip of black foam rubber (the sticky sided kind) at the lip of the flapper.

Simple answer to a nagging problem!

Pete

hj · Oct 30, 2006

vent

Often it is a case of the wind blowing across the face of the grille that creates a lower pressure than in the house and that pushes the flap open, then it closes because the two pressures equalize.

OldPete · Oct 30, 2006

Yeah, that sounds like what he said.

Foam tape idea sound solid to you, hj? Or any other ideas to shut it up?

Thanks, Pete

Terry · Feb 15, 2019

I simply used double sided 3M tape and attached a plastic washer at the bottom of the flapper. Worked PERFECTLY. Now it opens when it's turned on and makes ZERO flapping noise when it's not. Hope that helps!
Posted by user Loungeact

Vinh Vu · Mar 2, 2019

Terry,

Do you mind showing me a picture of what you did? I’m kind of slow. I have the same problem and I have two exhaust fans in the master bathroom; 1 in the toilet and 1 above the shower stand. So I have double the amount of noise when both making noises.

Thank you,

Vinh

Jadnashua · Mar 2, 2019

Basically, he added a weight to the flapper so it was less likely to be blown open except when the fan runs. How you attach the weight is up to you. Double-sided tape, epoxy, or maybe even a screw. It can't be too heavy, or it won't allow it to open when the fan runs. It's possible that the stuff is galvanized (many are aluminum), but if steel based, a small magnet should work, too.

Jcwrks · Oct 29, 2022

Sorry to resurrect an old thread. I too had the noisy flapper from my Nutone bathroom light/exhaust fan. I went into the attic and removed the snap on vent section. I cut a 3/4" (w) x 1/8" (thick) of high density foam pipe insulation that had adhesive on the edge. I placed it at the top center inside edge of the flapper. No more noise. Sadly it took me 6 years to become motivated enough to tackle this issue.

Darn "Flapper" won't shut up!

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