Whining fan

[Ed_B]

Hello all

My first post here. I ran a search but can't find anything on this at a first glance - let me know if there is something here already.

I have a fan in the bathroom. We live in a block and there's a constant - and pretty strong - draft up the vent shaft that turns the fan even when it's off.

That causes a whine, loud enough to keep us awake if we don't close the door. If I put a screwdriver in the vanes the fan and the whine both stop. It sounds like a harmonic or something.

I've checked for play in the fan, but there's nothing side to side. There's 3mm or so up and down - ie, the axle moves in or out of the motor by 3mm - but I can't see how that would cause it. I've cleared the fluff and dust out but that actually made the problem worse!

Any ideas what we might do to fix it, beyond getting a new fan? Any suggestions very gratefully received. Cheers!

 

[foxhole]

You need a baffle to prevent air movement when turned off.

 

[Ed_B]

Thank you, that's really helpful - I'd never heard of one.

Could I buy a baffle and just fit it in place of the current grille?

Simply Silent seems to be the most available option, and they do spares if we don't want the whole assembly:
https://www.redringxpelair.com/assets/xpelair/brochures/Xpelair-Simply-Silent.pdf

 

[Bosswhite]

A squirt of WD 40 might help !!

 

[Agile]

Many small extract fans have self closing louvres which only open when the fan is on.

It very slightly worries me if the fan is allowing air INTO your property. Check that with a match smoke or flame.

Sometimes boiler flues discharge into vent shafts and the air there may be less than wholesome ( to say the least ).

Tony

 

[Ed_B]

Thanks -- I thought about louvres but it's ceiling-mounted.

Thankfully the draft does seem to be out of the flat (- it's such a suck that I'm even wondering if we need our fan... I'm guessing there's a fan up on the roof, or else it's the regular breeze at 100ft up.)

 

[jj4091]

If the fan is being driven by air being sucked out of the room then a back draft shutter nor any other type of baffle or grill will not stop it. Cleaning the blades & lubricating the bearings(as has been suggested) may help reduce the noise. It may be easier to just fit a grill over the hole if you do not actually think you need an extractor, rather than buy a new one, as the problem will return again as it ages.