David has brought this to us :
Hi all,

This summer I installed a batroom extractor fan to reduce the
condensation when showering, etc - particularly in winter.
It's one of thos B&Q / Greenwood kits, ie through the ceiling to loft,
flexible pipe, out through soffit board under the eaves.
It was only £23 as I bought the version without "run-on" and operate
it simply from the bathroom light.

It seems to be doing a good job, but during the recent windy weather
particularly, I feel quite a draft entering the bathroom. I think this
will lead to significant heat loss and a less than hot bathroom which
I like.

Does anyone know if there is a "louvre" end cover that I can buy on
its own and ideally has the same 5" hole and screw footprint as the
B&Q/Greenwood.
Will the fan be powerfull enough to suck open the louvres if installed
at bathroom end, or blow them open if installed outside under soffit ?
Which end is preferred ?

Thanks.

David

When I installed ours, as part of the kit I fitted on the outside a
plastic 'flap valve'. A disk which filled the aperture pivoted off
centre, such that it would close under its own weight or if the wind
blew against it, yet the draft from the fan when it was turned on was
enough to open it fully.

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Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk