I've got a 100mm inline extractor fan in the ensuite; there's a vent in the
ceiling and it ducts the air up into the roofspace (in corrugated flexible
ducting) and as this is a dormer-style house with a very low roofline, it
passes down under the tiles in 100mm rigid flat ducting to a grille just
below the guttering.

It's really very ineffective though, and while I'm scrabbling around in the
roof space sorting out my downlighter wiring I thought I might try fixing
this too... I was considering replacing the 100mm fan with a 150mm model;
however, realistically there's no easy way to upgrade the length of fixed
100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I
would replace the flexible stuff in the roof space with 150mm ducting,
probably rigid rather than the flexible hose.

Question is, would that be worthwhile at all? Would the old 100mm section,
which I can't upgrade, just act as a bottleneck to eliminate any benefit?

Thanks

--
David

In message , Lobster
writes
I've got a 100mm inline extractor fan in the ensuite; there's a vent in the
ceiling and it ducts the air up into the roofspace (in corrugated flexible
ducting) and as this is a dormer-style house with a very low roofline, it
passes down under the tiles in 100mm rigid flat ducting to a grille just
below the guttering.

It's really very ineffective though, and while I'm scrabbling around in the
roof space sorting out my downlighter wiring I thought I might try fixing
this too... I was considering replacing the 100mm fan with a 150mm model;
however, realistically there's no easy way to upgrade the length of fixed
100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I
would replace the flexible stuff in the roof space with 150mm ducting,
probably rigid rather than the flexible hose.

Question is, would that be worthwhile at all? Would the old 100mm section,
which I can't upgrade, just act as a bottleneck to eliminate any benefit?

Thanks

Monrose do a high powered 100mm fan.
--
bert

On 15/02/2014 19:13, Lobster wrote:
I've got a 100mm inline extractor fan in the ensuite; there's a vent in the
ceiling and it ducts the air up into the roofspace (in corrugated flexible
ducting) and as this is a dormer-style house with a very low roofline, it
passes down under the tiles in 100mm rigid flat ducting to a grille just
below the guttering.

It's really very ineffective though, and while I'm scrabbling around in the
roof space sorting out my downlighter wiring I thought I might try fixing
this too... I was considering replacing the 100mm fan with a 150mm model;
however, realistically there's no easy way to upgrade the length of fixed
100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I
would replace the flexible stuff in the roof space with 150mm ducting,
probably rigid rather than the flexible hose.

Question is, would that be worthwhile at all? Would the old 100mm section,
which I can't upgrade, just act as a bottleneck to eliminate any benefit?

Thanks


Have you considered a mixed flow fan? They can deliver a good flow rate
under high resistance. I have a 100mm Vent Axia one which has about a
metre of flexible ductwork on each side and it vents out through a
dedicated roof vent tile. It works extremely well, the roof tile creates
a lot of resistance due to its design but the fan is still able to
deliver a decent flow rate.

http://www.vent-axia.com/product/acm...ns-acm100.html

--
Dawood

On Sat, 15 Feb 2014 19:13:39 GMT, Lobster wrote:

I've got a 100mm inline extractor fan in the ensuite; there's a vent in the
ceiling and it ducts the air up into the roofspace (in corrugated flexible
ducting) and as this is a dormer-style house with a very low roofline, it
passes down under the tiles in 100mm rigid flat ducting to a grille just
below the guttering.

It's really very ineffective though, and while I'm scrabbling around in the
roof space sorting out my downlighter wiring I thought I might try fixing
this too... I was considering replacing the 100mm fan with a 150mm model;
however, realistically there's no easy way to upgrade the length of fixed
100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I
would replace the flexible stuff in the roof space with 150mm ducting,
probably rigid rather than the flexible hose.

Question is, would that be worthwhile at all? Would the old 100mm section,
which I can't upgrade, just act as a bottleneck to eliminate any benefit?

Thanks

Rigid would, in itself, help, as corrugations cause a lot of drag.
--
Peter.
The gods will stay away
whilst religions hold sway

PeterC wrote in
:

On Sat, 15 Feb 2014 19:13:39 GMT, Lobster wrote:

I've got a 100mm inline extractor fan in the ensuite; there's a vent
in the ceiling and it ducts the air up into the roofspace (in
corrugated flexible ducting) and as this is a dormer-style house with
a very low roofline, it passes down under the tiles in 100mm rigid
flat ducting to a grille just below the guttering.

It's really very ineffective though, and while I'm scrabbling around
in the roof space sorting out my downlighter wiring I thought I might
try fixing this too... I was considering replacing the 100mm fan with
a 150mm model; however, realistically there's no easy way to upgrade
the length of fixed 100mm ducting (about 1-1.5m worth) which runs
under the roof tiles. I would replace the flexible stuff in the roof
space with 150mm ducting, probably rigid rather than the flexible
hose.

Question is, would that be worthwhile at all? Would the old 100mm
section, which I can't upgrade, just act as a bottleneck to eliminate
any benefit?

Thanks

Rigid would, in itself, help, as corrugations cause a lot of drag.

Corrugations also allow a build up of fluff.

What is meant by "mixed flow"?

--

DerbyBorn

---
This email is free from viruses and malware because avast! Antivirus protection is active.
http://www.avast.com

On 15/02/2014 23:12, DerbyBorn wrote:
PeterC wrote in
:

On Sat, 15 Feb 2014 19:13:39 GMT, Lobster wrote:

I've got a 100mm inline extractor fan in the ensuite; there's a vent
in the ceiling and it ducts the air up into the roofspace (in
corrugated flexible ducting) and as this is a dormer-style house with
a very low roofline, it passes down under the tiles in 100mm rigid
flat ducting to a grille just below the guttering.

It's really very ineffective though, and while I'm scrabbling around
in the roof space sorting out my downlighter wiring I thought I might
try fixing this too... I was considering replacing the 100mm fan with
a 150mm model; however, realistically there's no easy way to upgrade
the length of fixed 100mm ducting (about 1-1.5m worth) which runs
under the roof tiles. I would replace the flexible stuff in the roof
space with 150mm ducting, probably rigid rather than the flexible
hose.

Question is, would that be worthwhile at all? Would the old 100mm
section, which I can't upgrade, just act as a bottleneck to eliminate
any benefit?

Thanks

Rigid would, in itself, help, as corrugations cause a lot of drag.

Corrugations also allow a build up of fluff.

What is meant by "mixed flow"?



"In a mixed flow fan the air flows in both axial and radial direction
relative to the shaft. Mixed flow fans develops higher pressures than
axial fans."

Read mo http://www.engineeringtoolbox.com/fan-types-d_142.html
--
Dawood

Lobster wrote:
I've got a 100mm inline extractor fan in the ensuite; there's a vent in the
ceiling and it ducts the air up into the roofspace (in corrugated flexible
ducting) and as this is a dormer-style house with a very low roofline, it
passes down under the tiles in 100mm rigid flat ducting to a grille just
below the guttering.

It's really very ineffective though, and while I'm scrabbling around in the
roof space sorting out my downlighter wiring I thought I might try fixing
this too... I was considering replacing the 100mm fan with a 150mm model;
however, realistically there's no easy way to upgrade the length of fixed
100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I
would replace the flexible stuff in the roof space with 150mm ducting,
probably rigid rather than the flexible hose.

Question is, would that be worthwhile at all? Would the old 100mm section,
which I can't upgrade, just act as a bottleneck to eliminate any benefit?

Thanks


Is the fan the right way round? Yes, I know it's a stupid question!

"Lobster" wrote in message
. 236...
I've got a 100mm inline extractor fan in the ensuite; there's a vent in
the
ceiling and it ducts the air up into the roofspace (in corrugated flexible
ducting) and as this is a dormer-style house with a very low roofline, it
passes down under the tiles in 100mm rigid flat ducting to a grille just
below the guttering.

It's really very ineffective though, and while I'm scrabbling around in
the
roof space sorting out my downlighter wiring I thought I might try fixing
this too... I was considering replacing the 100mm fan with a 150mm model;
however, realistically there's no easy way to upgrade the length of fixed
100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I
would replace the flexible stuff in the roof space with 150mm ducting,
probably rigid rather than the flexible hose.

Question is, would that be worthwhile at all? Would the old 100mm section,
which I can't upgrade, just act as a bottleneck to eliminate any benefit?

There are two aspects to fans, the volume they shift and the pressure they
develop.
(As with all bladed pumps, centrifugal and axial)
It sounds like your fan does not develop enough pressure.

There are special high pressure fans for long ducts, usually centrifugal.

Assuming you can join them in a sloping kind of way, it will work, is all i
can say, as I've seen this sort ogf thing done via a reducer. I guess it
depends on how much 'oomph' the fan can deliver!
Brian

--
From the Sofa of Brian Gaff Reply address is active
"Lobster" wrote in message
. 236...
I've got a 100mm inline extractor fan in the ensuite; there's a vent in
the
ceiling and it ducts the air up into the roofspace (in corrugated flexible
ducting) and as this is a dormer-style house with a very low roofline, it
passes down under the tiles in 100mm rigid flat ducting to a grille just
below the guttering.

It's really very ineffective though, and while I'm scrabbling around in
the
roof space sorting out my downlighter wiring I thought I might try fixing
this too... I was considering replacing the 100mm fan with a 150mm model;
however, realistically there's no easy way to upgrade the length of fixed
100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I
would replace the flexible stuff in the roof space with 150mm ducting,
probably rigid rather than the flexible hose.

Question is, would that be worthwhile at all? Would the old 100mm section,
which I can't upgrade, just act as a bottleneck to eliminate any benefit?

Thanks

--
David

Lobster wrote:

I've got a 100mm inline extractor fan in the ensuite; there's a vent in the
ceiling and it ducts the air up into the roofspace (in corrugated flexible
ducting) and as this is a dormer-style house with a very low roofline, it
passes down under the tiles in 100mm rigid flat ducting to a grille just
below the guttering.

It's really very ineffective though, and while I'm scrabbling around in the
roof space sorting out my downlighter wiring I thought I might try fixing
this too... I was considering replacing the 100mm fan with a 150mm model;
however, realistically there's no easy way to upgrade the length of fixed
100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I
would replace the flexible stuff in the roof space with 150mm ducting,
probably rigid rather than the flexible hose.

Question is, would that be worthwhile at all? Would the old 100mm section,
which I can't upgrade, just act as a bottleneck to eliminate any benefit?

After recommendation here, I bought one of these:
http://www.tlc-direct.co.uk/Products...ENTslashT.html

Admittedly not cheap, but I was amazed by how quiet it was, I had
to feel the air to be sure it was running. The airflow is far
better than the (failed) cheap one it replaced. It can push-fit
into the pipework, and is readily removable for cleaning.

Chris
--
Chris J Dixon Nottingham UK


Plant amazing Acers.

On 16 Feb 2014, "harryagain" grunted:


"Lobster" wrote in message
. 236...
I've got a 100mm inline extractor fan in the ensuite; there's a vent
in the
ceiling and it ducts the air up into the roofspace (in corrugated
flexible ducting) and as this is a dormer-style house with a very low
roofline, it passes down under the tiles in 100mm rigid flat ducting
to a grille just below the guttering.

It's really very ineffective though, and while I'm scrabbling around
in the
roof space sorting out my downlighter wiring I thought I might try
fixing this too... I was considering replacing the 100mm fan with a
150mm model; however, realistically there's no easy way to upgrade
the length of fixed 100mm ducting (about 1-1.5m worth) which runs
under the roof tiles. I would replace the flexible stuff in the roof
space with 150mm ducting, probably rigid rather than the flexible
hose.

Question is, would that be worthwhile at all? Would the old 100mm
section, which I can't upgrade, just act as a bottleneck to eliminate
any benefit?

There are two aspects to fans, the volume they shift and the pressure
they develop.
(As with all bladed pumps, centrifugal and axial)
It sounds like your fan does not develop enough pressure.

There are special high pressure fans for long ducts, usually
centrifugal.

Yeah, I think the answer is maybe just to replace it with a 100mm
centrifugal model.

The plot thickens actually: the 150mm fan I was originally thinking of
going for was http://tinyurl.com/ma4xp3c (or
http://www.toolstation.com/shop/Elec...mm%20Part%20L%
20Inline
%20Shower%20Fan%20Kit%20with%20Timer/d190/sd280/p97314); however I
hadn't originally spotted that this doesn't coincide with the standard
ducting sizes which are 100mm or 125mm. Weird!


--
David

On Sunday, February 16, 2014 11:34:07 AM UTC, Chris J Dixon wrote:
Lobster wrote:



I've got a 100mm inline extractor fan in the ensuite; there's a vent in the

ceiling and it ducts the air up into the roofspace (in corrugated flexible

ducting) and as this is a dormer-style house with a very low roofline, it

passes down under the tiles in 100mm rigid flat ducting to a grille just

below the guttering.



It's really very ineffective though, and while I'm scrabbling around in the

roof space sorting out my downlighter wiring I thought I might try fixing

this too... I was considering replacing the 100mm fan with a 150mm model;

however, realistically there's no easy way to upgrade the length of fixed

100mm ducting (about 1-1.5m worth) which runs under the roof tiles. I

would replace the flexible stuff in the roof space with 150mm ducting,

probably rigid rather than the flexible hose.



Question is, would that be worthwhile at all? Would the old 100mm section,

which I can't upgrade, just act as a bottleneck to eliminate any benefit?



After recommendation here, I bought one of these:

http://www.tlc-direct.co.uk/Products...ENTslashT.html



Admittedly not cheap, but I was amazed by how quiet it was, I had

to feel the air to be sure it was running. The airflow is far

better than the (failed) cheap one it replaced. It can push-fit

into the pipework, and is readily removable for cleaning.



+1
Excellent fans, very quiet. That is until you control them with a triac controller, but that is a matter for the other post !
Simon.