Is there a spring on the backdraft damper missing? Or a foam strip?
Does the vent exit into any type of baffle to prevent the wind from causing too much backdraft?

 

Is there a spring on the backdraft damper missing? Or a foam strip?
Does the vent exit into any type of baffle to prevent the wind from causing too much backdraft?

The damper I am referring to is the built-in plastic, non-spring loaded damper installed on the Panasonic fan itself. I do not believe there is a phone strip, because I can hear the sound of plastic touching plastic. The vent exits to the roof which has the standard Home Depot purchased style damper with built in flapper style damper.

What is happening is that slight air pressure changes in the roof are causing the fan's built in plastic damper to ever so slightly lift and then drop. I'm mostly asking if anyone knows The Panasonic fans, and how to get to the fan's damper without removing it. I can fix it if that's the case.

 

Yeah it's annoying. Inline dampers help and the flush exterior dampers don't pick up in the wind like hooded ones

 

I just installed a Panasonic Whisper fan on Saturday. It's been windy the past 2 days. Not a single flap. You can access the flapper from inside. Pull down the vent cover, you can unplug the motor and with 3 or 4 screws drop the motor assembly. Should be able to see flapper and add some foam between the it and the plastic housing.

 

Perfect. That's what I'll do. Yeah, I didn't expect this to be the case given that there is a damper on the roof vent. Although, I hate those cheap Broan Nutone roof vents and most of what you can get walking into a big box store. We just didn't have available to us higher quality options due to COVID related backups in shipping.

 

We have changed out the exterior vent with a flap vent and removed the fan vent flap and it works great. It takes the flap vent to the exterior side of your home which is now muffled from the distance. The flaps that look like a window blind and not on a pendulum access point work best. Two Center points of contact on the flap will seem to always flap when windy.

good luck.

 

This was my preferred option when installing the bathroom fan in the first place, following the logic of the range hood manufacturer who recommended installing an in line roof damper over their plastic damper. I chickened out on removing the bathroom fan's similar damper when installing it.

I should point out that this is the slim line Panasonic fan meant to fit in tight spaces - it's oval shape rather than circular.

 

Interesting, thanks. Never paid much attention to it.

 

Here is the situation based on photographs I took from another Panasonic whisper thin fan. Because the flapper is in a vertical teeter type setup rather than those bifold style you get with round backdraft dampers, it's easily pulled up with the slightest amount of air pressure. Every time it comes up just a little bit and falls back and hits that little metal stopper, it makes that annoying sound.

 

Touch of weather strip foam on the flapper where it hits the stop. Done.

See pic I posted above 👍

 

Reach in with a caulk gun and put a small dab on the bottom side for weight.


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You have to address where the flap hits the stop. Adding only weight will make the bang louder unless you dampen the cause of the sound.

 

Depends on the size.

Big enough, it won’t move if it’s windy outside.


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It shouldn't be moving that much in the first place. However, his is moving. Because the percentage of that noise happening is already high, it would behoove him to stop the noise instead of trying to weigh the flapper down. If you were trying to eliminate the potential for the sound to happen, I could see adding some weight.

 

Ah hell, just glue the damper shut (or open....)

Tom

 

I did a bathroom job last winter where the home owner is having the same problem. It’s the master bath and at night when there in bed and it’s windy it is annoying. I installed a Broan roof hood for the fan exhaust and it points directly into the wind and blows the Broan aluminum flapper up and then the fan damper. I am going to go there this spring and see if I can use some coil stock and rivet some kind of a wind foil on to the hood.
nicko

 

One idea that comes to mind is using adhesive-backed weights, like those used for balancing ceiling fans, to weigh down the flappers. You can attach these weights to the flappers from the inside of the fan, making sure they're evenly distributed to avoid any wobbling.

How does that help? It also has to open to exhaust.

 

I had a similar issue and figured out that the flapper noise was from backdrafts and wind pushing against it. Sealing up gaps helped a bit, but what really made the difference was adding some acoustic treatment around the duct where it exits. I got some decent info from https://www.advanced-noise-solutions.co.uk/reduce-fan-noise/ that explained how airflow and vibration can add to the noise and how to cut it down.