stopping a storm coming through the extraction fan duct?

deandean

In the storm tonight there is a huge airflow out tbrough the kitchen extraction fan. There are a lot of accessories to prevent back drafts but they are not going to work here, the air flow in my case is out of the house. I reckon I need a motorized valve or similar in the 100 mm diameter duct. Like a motorised iris. Does such an item exit, does anyone know? It must be a common problem.
Thanks,
Dean

cast_iron

You can swap the fan out for one of these iCon ones.
When switched on, the iris opens are a few seconds and it closes when turned off.
About €60 to buy - they are a bit on the expensive side.

indie armada

you could fit an inline back draft shutter, cost about a fiver.

deandean

indie armada wrote: »

you could fit an inline back draft shutter, cost about a fiver.

Yea I know of those allright, thanks, my problem is that the flow of air is usually outwards, so it's not a back draft.

freddyuk

I fitted the inline back draft shutter horizontally above the ceiling grill so it rests closed. It will only open when the inline fan in the attic starts to suck. There are 2 tiny springs which hold it closed in vertical mode so I removed one of these to ease the pressure required to open it. If you have a massive gale blowing from inside to out then it may not work but for normal drafts it will.

onliner

It looks to me like to need to improve draft proofing in your house as air has to get in to cause it to exit via your kitchen hood.