I've fitted a hotpoint extractor hood from B&Q. Where this is fitted there was an ordinary extractor fan venting to the outside through the cavity wall via a 100mm PVC pipe. I want to vent the new cooker hood through the existing hole, but the top of the extractor has a 150mm round outlet. What is the best way to reduce this to 100mm to vent through the existing hole (which is at 90 degrees to the extractor so flexible conduit required). I've seen a 125mm to 100mm PVC collar in Screwfix, but not 150mm to 100mm anywhere.
Mkaing the hole in the wall bigger is not really an option! Thanks.

Pufter wrote:
I've fitted a hotpoint extractor hood from B&Q. Where this is fitted
there was an ordinary extractor fan venting to the outside through the
cavity wall via a 100mm PVC pipe. I want to vent the new cooker hood
through the existing hole, but the top of the extractor has a 150mm
round outlet. What is the best way to reduce this to 100mm to vent
through the existing hole (which is at 90 degrees to the extractor so
flexible conduit required). I've seen a 125mm to 100mm PVC collar in
Screwfix, but not 150mm to 100mm anywhere.
Mkaing the hole in the wall bigger is not really an option! Thanks.

Try http://www.bes.ltd.uk - they're normally the best place to try for
this sort of stuff.

David

On Tue, 17 May 2005 18:54:30 GMT, Lobster
wrote:

Pufter wrote:
I've fitted a hotpoint extractor hood from B&Q. Where this is fitted
there was an ordinary extractor fan venting to the outside through the
cavity wall via a 100mm PVC pipe. I want to vent the new cooker hood
through the existing hole, but the top of the extractor has a 150mm
round outlet. What is the best way to reduce this to 100mm to vent
through the existing hole (which is at 90 degrees to the extractor so
flexible conduit required). I've seen a 125mm to 100mm PVC collar in
Screwfix, but not 150mm to 100mm anywhere.
Mkaing the hole in the wall bigger is not really an option! Thanks.

Try http://www.bes.ltd.uk - they're normally the best place to try for
this sort of stuff.

Look at 11494 - 125 mm i.d. to 100 mm o.d., white
and 11495 - 150 mm i.d. to 125 mm o.d., white

Bear in mind that 100mm dia pipe will create much more back pressure
than 150mm pipe!

Mark.

"Mark" wrote in message
...
On Tue, 17 May 2005 18:54:30 GMT, Lobster
wrote:

Pufter wrote:
I've fitted a hotpoint extractor hood from B&Q. Where this is fitted
there was an ordinary extractor fan venting to the outside through the
cavity wall via a 100mm PVC pipe. I want to vent the new cooker hood
through the existing hole, but the top of the extractor has a 150mm
round outlet. What is the best way to reduce this to 100mm to vent
through the existing hole (which is at 90 degrees to the extractor so
flexible conduit required). I've seen a 125mm to 100mm PVC collar in
Screwfix, but not 150mm to 100mm anywhere.
Mkaing the hole in the wall bigger is not really an option! Thanks.

Try http://www.bes.ltd.uk - they're normally the best place to try for
this sort of stuff.

Look at 11494 - 125 mm i.d. to 100 mm o.d., white
and 11495 - 150 mm i.d. to 125 mm o.d., white

Bear in mind that 100mm dia pipe will create much more back pressure
than 150mm pipe!

You should worry! My toilet extractor fan (Xpelair) vents through a 75mm
pipe that runs through the flat roof to the fascia about 3-4m. You can't buy
extractor fans with smaller than 100mm outlets now (not that I can see). I
can't shove a bigger pipe through as it's full of insulation. Meanwhile the
fan bearing gets noisier and noisier ( Any suggestions, likewise,
welcome!

My kitchen extraction also runs parallel in 75mm pipe for about 2m. I had to
convert right down to that - it still extracts enough but much slower than
it would with a bigger pipe, and much noisier. The flow is also non-linear
with fan speed, there's no point running it other than at the first position
as the noise goes up exponentially and the extraction just a bit!


--
Bob Mannix
(anti-spam is as easy as 1-2-3 - not)

On Wed, 18 May 2005 12:15:05 +0100, "Bob Mannix"
wrote:

Bear in mind that 100mm dia pipe will create much more back pressure
than 150mm pipe!

You should worry! My toilet extractor fan (Xpelair) vents through a 75mm
pipe that runs through the flat roof to the fascia about 3-4m. You can't buy
extractor fans with smaller than 100mm outlets now (not that I can see). I
can't shove a bigger pipe through as it's full of insulation. Meanwhile the
fan bearing gets noisier and noisier ( Any suggestions, likewise,
welcome!

Can you take out some insulation and then run a 100mm pipe through?
If you can't do this you could look at reducing the speed of the fan
or buying a stronger fan!

My kitchen extraction also runs parallel in 75mm pipe for about 2m. I had to
convert right down to that - it still extracts enough but much slower than
it would with a bigger pipe, and much noisier. The flow is also non-linear
with fan speed, there's no point running it other than at the first position
as the noise goes up exponentially and the extraction just a bit!

I found it worthwhile to replace the pipework in my kitchen with
larger diameter round pipe. It made a big difference.

Mark