Bathroom extract fan problem
 

This is another problem of the "where to put the isolator switch" fan!

Over the week-end we did the first part of the flat bathroom
refurbishment. We've put up the false ceiling and the new lighting
without too much problem.

However the extract fan is going to be difficult. The original
fan doesn't work so needs replacing, on removing the old fan I found
that it has a completely inaccessible junction box mounted a couple of
feet down the service duct which is brick with no access holes near
where the junction box is! How they got it there I'll never know.
OK, so I can simply ignore the old wiring (I have found the other end
of it so have disconnected that) and put new wiring in.

The real problem is that the old extract fan uses what looks like a 2"
or so diameter tube up the service duct for the extract. Are there
any currently available fans which can produce a reasonably effective
extract up such a small diameter pipe? If so where am I likely to be
able to get one? I would guess that the tube must be quite long as it
(hopefully) runs up through two storeys to the roof.

Alternatively can I just extract into the service duct? Is this
allowed in general or would it depend on the particular block of
flats? I think there is only one other 'internal' bathroom in the
block.

I *might* be able to extract into the old gas flue (the new gas boiler
has been moved and has fan assisted flues which no longer use the
service duct). I'd prefer not to do this though as it would be lots
of hassle and I don't even know if the old flue is still in place
and/or hasn't been blocked up.

--
Chris Green )