On Sat, 17 Oct 2020 21:04:26 +0100, Mike Clarke wrote:

On 17/10/2020 15:17, PeterC wrote:

I do like the backdraught shutter - just 2 pieces of plastic that open very
easily and won't clatter in the wind.

If they're anything like the ones on my Ventaxia bathroom fan they WILL
clatter.

The present vanes are the typical louvres of plastic and on the outside of
the duct. Those on the new fan probably have less material than ¼ of one of
the present ones and not sufficiently rigid to clatter as loudly; they're
also at the rear of the fan.
I'll prop open the outside ones (might be able to do it from inside) just as
a matter of interest - disadvantage is that insects can get into the duct.
--
Peter.
The gods will stay away
whilst religions hold sway