How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it
doesn't keep pace with the steam during a shower. It feeds a one metre
pipe into a chimney. Am I being too optimistic? The room clears fairly
quickly after the shower goes off. But SWMBO thinks the room should stay
clear. Perhaps I need to go up to an inline one with higher throughput?
I do keep the door slightly open and I don't think the chimney is blocked.

Peter Scott

You get what you pay for - except where idiot marketing take the ****.

Cheap fans
Cheap bearings which get noisy, hopefully before they seize which is
when nasty things happen.

Xpelair.
Quality bearings with a long life, typically electronic control or
shutters breaks first. The GX range and others are UK packaging around
contract manufactured German EBM-Papst motor & bearing. You can
usually find EBM or EBM-Papst embossed on the motor casting.

Vent Axia.
Can not recall, often more expensive, typically more commercial in
focus (better shutters).

The problem with AC fans is when the bearings seize.
A fan by its nature suffers lint adhesion to fan impellor and
particularly motor body. Lint is highly insulatory and highly
flammable. When bearings seize on a DC fan the electronics detect the
stalled condition and turn current on & off - so limiting motor
heating. When bearing seize on an AC fan there are no electronics just
a bimetallic strip that opens & closes based on the temperature of the
motor. In some cases this bimetallic strip is not present, arcs badly
with a stalled inductive load or operates at too high a temperature
with the result that the assembly overheats - no fan means no airflow.
Overheating can be sufficient, given long enough, to result in lint
igniting - particularly if combined with oil leakage from worn
bearings or grease from kitchen extractor usage.

In industrial settings AC fans are typically metal housing, metal
impellor, metal struts, metal motor enclosure to act as a heatsink and
a bimetallic strip thermal cutout. Loss of cooling is usually noticed
by widgets no longer moving or secondary overheat alarms.

In domestic settings a lot of cheap fans use low temperature
thermoplastic motor-struts, impellors, housings and may not include a
bimetallic cutout (or at least one functioning correctly). Some are
more prone to lint buildup due to impellor design and low grade
bearings will deposit a continual stream of ejected lubricant due to
inadequate seals & dust ingress wear.

This problem applies to extractor fans, cooker hoods (grease buildup),
tumble dryers (fine lint builds up past the filter ready to flambe)
and dehumidifiers (which use cheap motors & bearings).

Always check Ebay, you can sometimes pick up boxed new Vent Axia &
Xpelair at good prices. The bad news is that they continually change -
eg, parts for 1995-97, 98-01, 02-05, 06-present. So you may a) not be
able to get parts if too old b) need to check carefully exactly what
parts are required.

It is sad that DC fans have not replaced AC totally now - although
that will introduce low quality DC power supply failures (cue being
sold separately at inflated parts prices).

"Peter Scott" wrote in message
...
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it doesn't
keep pace with the steam during a shower. It feeds a one metre pipe into a
chimney. Am I being too optimistic? The room clears fairly quickly after
the shower goes off. But SWMBO thinks the room should stay clear. Perhaps
I need to go up to an inline one with higher throughput? I do keep the
door slightly open and I don't think the chimney is blocked.

Peter Scott


Do you have satisfactory arrangements to allow 85 cubic metres of fresh sry
air into the room - without resistance?

"John" wrote in message
...

"Peter Scott" wrote in message
...
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it doesn't
keep pace with the steam during a shower. It feeds a one metre pipe into
a chimney. Am I being too optimistic? The room clears fairly quickly
after the shower goes off. But SWMBO thinks the room should stay clear.
Perhaps I need to go up to an inline one with higher throughput? I do
keep the door slightly open and I don't think the chimney is blocked.

Peter Scott


Do you have satisfactory arrangements to allow 85 cubic metres of fresh
sry air into the room - without resistance?



....fresh Dry air.....

Many people miss this important aspect - it is so important.(otherwise you
are trying in vain to create a vacuum)

"Peter Scott" wrote in message
...
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it doesn't
keep pace with the steam during a shower. It feeds a one metre pipe into a
chimney. Am I being too optimistic? The room clears fairly quickly after
the shower goes off. But SWMBO thinks the room should stay clear. Perhaps
I need to go up to an inline one with higher throughput? I do keep the
door slightly open and I don't think the chimney is blocked.

Peter Scott

I think that you are a little too optimistic.
I recently fitted an inline fan that extracts 220 cubic metres per hour for
a customer. I can assure you that the shower still steams up the room when
in use. I left the fan with a 10 minute timer overrun, however the room is
clear after 2 minutes.

Adam

ARWadsworth wrote:

"Peter Scott" wrote in message
...
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it
doesn't keep pace with the steam during a shower. It feeds a one metre
pipe into a chimney. Am I being too optimistic? The room clears fairly
quickly after the shower goes off. But SWMBO thinks the room should
stay clear. Perhaps I need to go up to an inline one with higher
throughput? I do keep the door slightly open and I don't think the
chimney is blocked.

Peter Scott

I think that you are a little too optimistic.
I recently fitted an inline fan that extracts 220 cubic metres per hour
for a customer. I can assure you that the shower still steams up the
room when in use. I left the fan with a 10 minute timer overrun, however
the room is clear after 2 minutes.

Adam

Thanks. That's reassuring, and will get me out of trying another one.
I've got expert opinions to back me up now!

Yes, I have avoided lack of air by opening the door a small amount. The
house is well sealed but has open but unused chimneys so I think the air
flow will not be impeded.

Peter Scott

"Peter Scott" wrote in message
...
ARWadsworth wrote:

"Peter Scott" wrote in message
...
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it
doesn't keep pace with the steam during a shower. It feeds a one metre
pipe into a chimney. Am I being too optimistic? The room clears fairly
quickly after the shower goes off. But SWMBO thinks the room should stay
clear. Perhaps I need to go up to an inline one with higher throughput?
I do keep the door slightly open and I don't think the chimney is
blocked.

Peter Scott

I think that you are a little too optimistic.
I recently fitted an inline fan that extracts 220 cubic metres per hour
for a customer. I can assure you that the shower still steams up the room
when in use. I left the fan with a 10 minute timer overrun, however the
room is clear after 2 minutes.

Adam

Thanks. That's reassuring, and will get me out of trying another one. I've
got expert opinions to back me up now!

Yes, I have avoided lack of air by opening the door a small amount. The
house is well sealed but has open but unused chimneys so I think the air
flow will not be impeded.

Peter Scott


Drawing air down a chimney is not an "easy" route for the air.

Would a dedicated air vent in the bathroom be possible?

In article ,
"js.b1" writes:
You get what you pay for - except where idiot marketing take the ****.

Cheap fans
Cheap bearings which get noisy, hopefully before they seize which is
when nasty things happen.

The Manroses originally installed in this house all seized
(silently) and burned out their motor windings (no resettable
thermal trip - not designed to be repairable).

Replaced with Deta. Had one seize, but it has a resetable trip,
so I repaired it, and it's worked fine ever since. Sadly, they
don't seem to be in business anymore. Mine have thermal solenoid
operated shutters.

Also have a Vent Axia which I picked up for peanuts but should
have been very expensive, and it's run for years with no issues.
Has magnetic solenoid operated shutters too.

I was given a second-hand Xpelair which is 30 years old. Ran
continuously for 10 years before I got it, and I've used it
during the summers since. This year, it started seizing, being
slow to start up. I cleaned and oiled the bearings and it worked
for several more months, but is starting to do it again now.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

"Andrew Gabriel" wrote in message
...
In article
,
"js.b1" writes:
You get what you pay for - except where idiot marketing take the ****.

Cheap fans
Cheap bearings which get noisy, hopefully before they seize which is
when nasty things happen.

The Manroses originally installed in this house all seized
(silently) and burned out their motor windings (no resettable
thermal trip - not designed to be repairable).

Replaced with Deta. Had one seize, but it has a resetable trip,
so I repaired it, and it's worked fine ever since. Sadly, they
don't seem to be in business anymore. Mine have thermal solenoid
operated shutters.

Also have a Vent Axia which I picked up for peanuts but should
have been very expensive, and it's run for years with no issues.
Has magnetic solenoid operated shutters too.

I was given a second-hand Xpelair which is 30 years old. Ran
continuously for 10 years before I got it, and I've used it
during the summers since. This year, it started seizing, being
slow to start up. I cleaned and oiled the bearings and it worked
for several more months, but is starting to do it again now.

Would synthetic high melting point grease be better on the fan bearings?
Although buying this sort of grease is not cheap.

"the_constructor" wrote in message
...
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Manrose are cheap, noisy tat. Buy Xpelair or Ventaxia.

In article ,
"Doctor Drivel" writes:

"Andrew Gabriel" wrote in message
...
I was given a second-hand Xpelair which is 30 years old. Ran
continuously for 10 years before I got it, and I've used it
during the summers since. This year, it started seizing, being
slow to start up. I cleaned and oiled the bearings and it worked
for several more months, but is starting to do it again now.

Would synthetic high melting point grease be better on the fan bearings?
Although buying this sort of grease is not cheap.

Bearings don't get hot, and I suspect they need a low friction oil.
They're lubricated by a tiny amount of oil in the phosphor bronze
(or on some, just by a high lead content phosphor bronze alloy).
I think the problem is caused by dust eventially getting into the
bearing. Cleaning this out helps, but it has scored the shaft.
Only oil I have to hand is (clean) engine oil, and I suspect that's
much to viscous to be absorbed into the bearing surface.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Mon, 5 Oct 2009 13:21:54 +0000 (UTC), Andrew Gabriel wrote:

In article ,
"Doctor Drivel" writes:

"Andrew Gabriel" wrote in message
...
I was given a second-hand Xpelair which is 30 years old. Ran
continuously for 10 years before I got it, and I've used it
during the summers since. This year, it started seizing, being
slow to start up. I cleaned and oiled the bearings and it worked
for several more months, but is starting to do it again now.

Would synthetic high melting point grease be better on the fan bearings?
Although buying this sort of grease is not cheap.

Bearings don't get hot, and I suspect they need a low friction oil.
They're lubricated by a tiny amount of oil in the phosphor bronze
(or on some, just by a high lead content phosphor bronze alloy).
I think the problem is caused by dust eventially getting into the
bearing. Cleaning this out helps, but it has scored the shaft.
Only oil I have to hand is (clean) engine oil, and I suspect that's
much to viscous to be absorbed into the bearing surface.

Last time I replaced a plain bearing it needed oil as it was dry. Doing it
at work enabled the use of vac. pump - amazing amount of air came out -
then let atmospheric pressure push the oil in.
This method might not be possible at home, but heating the oil with the
bearing in it (poss. 70 - 80C should be OK and not damage anything) then
letting it cool would get a lot more oil in to the bearing.
Assuming that the bearing can be removed - not a good method if not.
--
Peter.
The head of a pin will hold more angels if
it's been flattened with an angel-grinder.

On 4 Oct, 16:21, Peter Scott wrote:
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it
doesn't keep pace with the steam during a shower. It feeds a one metre
pipe into a chimney. Am I being too optimistic? The room clears fairly
quickly after the shower goes off. But SWMBO thinks the room should stay
clear. Perhaps I need to go up to an inline one with higher throughput?
I do keep the door slightly open and I don't think the chimney is blocked.

Peter Scott

I recently replaced the extractor in our downstairs toilet with one of
these: http://www.tlc-direct.co.uk/Products/SLTD160T.html
The builders had installed a normal bathroom fan, with almost 3m of
flexi ducting, including 2 90 degree bends, so the net effect was
absolutely no extraction at all. The new one howls a bit, you
certainly know it's working, but it clears the room of bad smells in a
few seconds.
Going to use the slightly more powerful version (
http://www.tlc-direct.co.uk/Products/SLTD250T.html ) in the upstairs
bathroom which has similarly found itself in the middle of the house
with a long run of ducting when we put an extension on the side of the
house.

"pcb1962" wrote in message
...
On 4 Oct, 16:21, Peter Scott wrote:
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it
doesn't keep pace with the steam during a shower. It feeds a one metre
pipe into a chimney. Am I being too optimistic? The room clears fairly
quickly after the shower goes off. But SWMBO thinks the room should stay
clear. Perhaps I need to go up to an inline one with higher throughput?
I do keep the door slightly open and I don't think the chimney is
blocked.

Peter Scott

I recently replaced the extractor in our downstairs toilet with one of
these: http://www.tlc-direct.co.uk/Products/SLTD160T.html
The builders had installed a normal bathroom fan, with almost 3m of
flexi ducting, including 2 90 degree bends, so the net effect was
absolutely no extraction at all. The new one howls a bit, you
certainly know it's working, but it clears the room of bad smells in a
few seconds.
Going to use the slightly more powerful version (
http://www.tlc-direct.co.uk/Products/SLTD250T.html ) in the upstairs
bathroom which has similarly found itself in the middle of the house
with a long run of ducting when we put an extension on the side of the
house.

Swapping the flexi ducting with proper pipe also helps.

Adam

On 5 Oct, 18:23, "ARWadsworth" wrote:
"pcb1962" wrote in message

...



On 4 Oct, 16:21, Peter Scott wrote:
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it
doesn't keep pace with the steam during a shower. It feeds a one metre
pipe into a chimney. Am I being too optimistic? The room clears fairly
quickly after the shower goes off. But SWMBO thinks the room should stay
clear. Perhaps I need to go up to an inline one with higher throughput?
I do keep the door slightly open and I don't think the chimney is
blocked.

Peter Scott

I recently replaced the extractor in our downstairs toilet with one of
these:http://www.tlc-direct.co.uk/Products/SLTD160T.html
The builders had installed a normal bathroom fan, with almost 3m of
flexi ducting, including 2 90 degree bends, so the net effect was
absolutely no extraction at all. The new one howls a bit, you
certainly know it's working, but it clears the room of bad smells in a
few seconds.
Going to use the slightly more powerful version (
http://www.tlc-direct.co.uk/Products/SLTD250T.html) in the upstairs
bathroom which has similarly found itself in the middle of the house
with a long run of ducting when we put an extension on the side of the
house.

Swapping the flexi ducting with proper pipe also helps.

Adam

Yes I did that, I think that's the cause of the 'howl', I'm sure the
flexible ducting would be quieter, though more restrictive.

Drawing air down a chimney is not an "easy" route for the air.

Would a dedicated air vent in the bathroom be possible?



No. It's right in the middle of the house with no external wall or
window. Walled in by an extension. Thanks for the suggestion

Peter Scott

pcb1962 wrote:
On 4 Oct, 16:21, Peter Scott wrote:
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?
Kindest regards,
Jim
cheap and cheerful, go noisey after a couple of years useually driving
customer nuts before complete failure. (depends on useage of course).
Allan
I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it
doesn't keep pace with the steam during a shower. It feeds a one metre
pipe into a chimney. Am I being too optimistic? The room clears fairly
quickly after the shower goes off. But SWMBO thinks the room should stay
clear. Perhaps I need to go up to an inline one with higher throughput?
I do keep the door slightly open and I don't think the chimney is blocked.

Peter Scott

I recently replaced the extractor in our downstairs toilet with one of
these: http://www.tlc-direct.co.uk/Products/SLTD160T.html
The builders had installed a normal bathroom fan, with almost 3m of
flexi ducting, including 2 90 degree bends, so the net effect was
absolutely no extraction at all. The new one howls a bit, you
certainly know it's working, but it clears the room of bad smells in a
few seconds.
Going to use the slightly more powerful version (
http://www.tlc-direct.co.uk/Products/SLTD250T.html ) in the upstairs
bathroom which has similarly found itself in the middle of the house
with a long run of ducting when we put an extension on the side of the
house.


It was my first experience of ducting, so I'm finding out as I go. It
seems to be a good idea to keep it fairly stretched or it might
collapse. Perhaps this has happened with yours?

Peter Scott

Andrew Gabriel wrote:
In article ,
"js.b1" writes:
You get what you pay for - except where idiot marketing take the ****.

Cheap fans
Cheap bearings which get noisy, hopefully before they seize which is
when nasty things happen.

The Manroses originally installed in this house all seized
(silently) and burned out their motor windings (no resettable
thermal trip - not designed to be repairable).

Replaced with Deta. Had one seize, but it has a resetable trip,
so I repaired it, and it's worked fine ever since. Sadly, they
don't seem to be in business anymore. Mine have thermal solenoid
operated shutters.

Also have a Vent Axia which I picked up for peanuts but should
have been very expensive, and it's run for years with no issues.
Has magnetic solenoid operated shutters too.

I was given a second-hand Xpelair which is 30 years old. Ran
continuously for 10 years before I got it, and I've used it
during the summers since. This year, it started seizing, being
slow to start up. I cleaned and oiled the bearings and it worked
for several more months, but is starting to do it again now.


Seems like it's a good idea to pay a bit then?

Peter Scott

"pcb1962" wrote in message
...
On 5 Oct, 18:23, "ARWadsworth" wrote:
"pcb1962" wrote in message

...



On 4 Oct, 16:21, Peter Scott wrote:
Allan Mac wrote:
On 4 Oct, 09:32, "the_constructor"
wrote:
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim

cheap and cheerful, go noisey after a couple of years useually
driving
customer nuts before complete failure. (depends on useage of
course).
Allan

I've replaced a ceiling fan with a new one pumping 85 cubic metres per
hour. I am a bit disappointed with the performance. The calculations
suggest it should clear the whole room in six minutes. However it
doesn't keep pace with the steam during a shower. It feeds a one metre
pipe into a chimney. Am I being too optimistic? The room clears fairly
quickly after the shower goes off. But SWMBO thinks the room should
stay
clear. Perhaps I need to go up to an inline one with higher
throughput?
I do keep the door slightly open and I don't think the chimney is
blocked.

Peter Scott

I recently replaced the extractor in our downstairs toilet with one of
these:http://www.tlc-direct.co.uk/Products/SLTD160T.html
The builders had installed a normal bathroom fan, with almost 3m of
flexi ducting, including 2 90 degree bends, so the net effect was
absolutely no extraction at all. The new one howls a bit, you
certainly know it's working, but it clears the room of bad smells in a
few seconds.
Going to use the slightly more powerful version (
http://www.tlc-direct.co.uk/Products/SLTD250T.html) in the upstairs
bathroom which has similarly found itself in the middle of the house
with a long run of ducting when we put an extension on the side of the
house.

Swapping the flexi ducting with proper pipe also helps.

Adam

Yes I did that, I think that's the cause of the 'howl', I'm sure the
flexible ducting would be quieter, though more restrictive.

Did you seal all the joints with gaffer tape? The one I fitted is very quiet
inside the house. You can hear it in the garden though.

Adam

On Oct 5, 5:57*pm, pcb1962 wrote:
I recently replaced the extractor in our downstairs toilet with one of
these:http://www.tlc-direct.co.uk/Products/SLTD160T.html

The other benefit of inline is that you can have multiple inlets.

I've wanted to try one inlet above a microwave, then another to a
gutted "designer" cooker hood. That way you can use a ****-off
powerful inline fan, even a controller, which covers everything. Stick
a waste disposal unit on the end and really go for it - burnt the
toast, no worries, just wave it next to the intake and whooshhh.

In article ,
"js.b1" writes:
On Oct 5, 5:57*pm, pcb1962 wrote:
I recently replaced the extractor in our downstairs toilet with one of
these:http://www.tlc-direct.co.uk/Products/SLTD160T.html
The other benefit of inline is that you can have multiple inlets.
I've wanted to try one inlet above a microwave, then another to a
gutted "designer" cooker hood. That way you can use a ****-off
powerful inline fan, even a controller, which covers everything. Stick
a waste disposal unit on the end and really go for it - burnt the
toast, no worries, just wave it next to the intake and whooshhh.

What I don't understand with the inline fans, is why on earth
don't they use a centrifugal blower rather than axial?
Much more effective where you have the pressure drop of
ducting to handle, and (can be) much quieter too.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel
wibbled on Tuesday 06 October 2009 14:19

In article
,
"js.b1" writes:
On Oct 5, 5:57*pm, pcb1962 wrote:
I recently replaced the extractor in our downstairs toilet with one of
these:http://www.tlc-direct.co.uk/Products/SLTD160T.html
The other benefit of inline is that you can have multiple inlets.
I've wanted to try one inlet above a microwave, then another to a
gutted "designer" cooker hood. That way you can use a ****-off
powerful inline fan, even a controller, which covers everything. Stick
a waste disposal unit on the end and really go for it - burnt the
toast, no worries, just wave it next to the intake and whooshhh.

What I don't understand with the inline fans, is why on earth
don't they use a centrifugal blower rather than axial?
Much more effective where you have the pressure drop of
ducting to handle, and (can be) much quieter too.


Can't you get centifugal? I didn't investigate because axial is the only one
that would fit between the wood upstairs (300mm or so gap) and even then I
had to be careful to choose a really slimline one...


--
Tim Watts

This space intentionally left blank...

On Oct 6, 2:19*pm, (Andrew Gabriel) wrote:
In article ,
* * * * "js.b1" writes:

On Oct 5, 5:57*pm, pcb1962 wrote:
I recently replaced the extractor in our downstairs toilet with one of
these:http://www.tlc-direct.co.uk/Products/SLTD160T.html
The other benefit of inline is that you can have multiple inlets.
I've wanted to try one inlet above a microwave, then another to a
gutted "designer" cooker hood. That way you can use a ****-off
powerful inline fan, even a controller, which covers everything. Stick
a waste disposal unit on the end and really go for it - burnt the
toast, no worries, just wave it next to the intake and whooshhh.

What I don't understand with the inline fans, is why on earth
don't they use a centrifugal blower rather than axial?
Much more effective where you have the pressure drop of
ducting to handle, and (can be) much quieter too.

I have wondered it too - however they might not be "axial".

Three fan types - axial, diagonal & radial...
- axial airflow - lots of airflow, relatively low pressure
- diagonal - lower airflow, higher pressure
- radial - lowest airflow, very high pressure

An axial & diagonal flow fan look identical - both "axial". The
difference is a diagonal flow fan has an impellor which has a
noticeable diagonal slant to the hub from one side to the other,
thereby producing more pressure than a conventional "axial flow" fan.
The disadvantage is they can produce a lot less airflow without RPM
and often more noise with backpressure interactions (ducting).

I have seen a few "axial duct" fans which are in fact diagonal flow,
they were pricey.

The new "trend" appears to be sticking the fan outside on the surface,
so you can have 500-800m^3 without any noise inside. Not a bad idea,
although sticking it recessed into the outer wall would be better re
acoustic mass than surface.

The only difference for a diagonal-flow fan is the impellor. EBM-Papst
seem to have reduced their range of "DV" fans, but I'm surprised the
common Xpelair axial have not used DV impellors - probably because
they are more interested in a micro-managed upgrade cycle of axial -
radial (centrifugal) - DC fan - humidistat controlled - air
recovery expensive-box.

"the_constructor" wrote in message
...
How do Manrose extractor fans compare with Xpelair and Ventaxia ?

Kindest regards,

Jim


Having read all the advice offered, I have now purchased an Xpelair GXC6 and
am going to contact the DG Installer and ask him to call round and measure
up, now I know what size hole I want in the DG Unit.

Thanks all