Magnetically enhanced back-draft damper

[Old_Badger]

I once read a suggestion that a magnet might be used to fully close back-draft dampers. The general response was that magnets would be too strong.
You might like to know that have now used a magnet successfully and it works well. There is a satisfying 'knock' as the damper is pulled right in.
The trick is to have the magnet at just the right distance from a small piece of steel fixed to the damper. If the distance is too far then the magnet won't overcome 'the pull-in distance'. If the magnet is too close then the fan won't blow the damper open.

 

[chirpychippy]

I once read a suggestion that a magnet might be used to fully close back-draft dampers. The general response was that magnets would be too strong.
You might like to know that have now used a magnet successfully and it works well. There is a satisfying 'knock' as the damper is pulled right in.
The trick is to have the magnet at just the right distance from a small piece of steel fixed to the damper. If the distance is too far then the magnet won't overcome 'the pull-in distance'. If the magnet is too close then the fan won't blow the damper open.

Whilst frequenting the bathroom last night I was wondering what I could use to stop the wind from howling through the bathroom extractor and making the bathroom really cold.

I'll look forwards to seeing you on Dragons Den

 

[Old_Badger]

Thanks for your reply Chirpychirpy. No chance of going on Dragons Den! Magnetically Enhancing a back-draft damper is only for people willing to make something to suit their own system, I think.

 

[foxhole]

I once read a suggestion that a magnet might be used to fully close back-draft dampers. The general response was that magnets would be too strong.
You might like to know that have now used a magnet successfully and it works well. There is a satisfying 'knock' as the damper is pulled right in.
The trick is to have the magnet at just the right distance from a small piece of steel fixed to the damper. If the distance is too far then the magnet won't overcome 'the pull-in distance'. If the magnet is too close then the fan won't blow the damper open.

Simple cowl tends to prevent backdraft in many cases .