[the_constructor]

Just out of curiosity, are 12V timer fans noisier than 240V fans....?

I got a 12V fan and my neighbour nearly jumps out of her skin when it is
switched on.

I installed it correctly a few months ago but after a week I disconnected
it.

It must be bad though because I can hear it downstairs through 3 closed
doors.

The fan is from Screwfix....

James

[Palindrome]

the_constructor wrote:
Just out of curiosity, are 12V timer fans noisier than 240V fans....?

I got a 12V fan and my neighbour nearly jumps out of her skin when it is
switched on.

I installed it correctly a few months ago but after a week I disconnected
it.

It must be bad though because I can hear it downstairs through 3 closed
doors.

The fan is from Screwfix....

Check out the rotational speed. For a given airflow, the DC fan solution
of a higher rotational speed is cheaper than the ac fan solution of
redesigned fan blades. Unfortunately, it tends to also be a noisier
solution. DC fans tend to have higher starting torques, so the onset of
the noise is much more sudden, too.

One of the advantages of DC fans is that it is usually very easy to
decrease the fan speed and hence greatly reduce the noise. Simply by
lowering the DC voltage. Even a small reduction in voltage (eg a couple
of diodes in series with the supply) can make a great difference.

--
Sue

[Andy Hall]

On 2008-02-24 12:09:36 +0000, "the_constructor"
said:


Just out of curiosity, are 12V timer fans noisier than 240V fans....?

It depends.

There are several factors:

- Fan size. A larger one under-run will be much quieter than a small
one run at max setting

- axial/centrifugal. Centrifugal fans can have more throughput and
are able to move air through a long duct better than axial fans.
However, they are noisier.

- bearings and motor. This relates to the manufacturer and quality
of the product.

- mounting. A fan mounted directly to a plasterboard wall or
especially ceiling has a very good sounding board to amplify the sound.


I got a 12V fan and my neighbour nearly jumps out of her skin when it is
switched on.

I installed it correctly a few months ago but after a week I disconnected
it.

It must be bad though because I can hear it downstairs through 3 closed
doors.

The fan is from Screwfix....

Mmmm.....

Take a look at the LoWatt range from Vent Axia. I fitted one of
these in my cloakroom. It is suitable for bathrooms as well and runs
from 12v. Very quiet indeed. I fitted it using rubber mounts and
sealing gasket, which reduces the sound yet further.

[ARWadworth]

"the_constructor" wrote in message
...

Just out of curiosity, are 12V timer fans noisier than 240V fans....?

A 12V fan by manufacturer A maybe a lot quiter than a 240V fan made by
manufactuer B. Quality counts. Greenwood and Vent Axia are good makes.

I got a 12V fan and my neighbour nearly jumps out of her skin when it is
switched on.

I installed it correctly a few months ago but after a week I disconnected
it.

Is it an inline fan mounted onto a joist? You need to isolate the fan from
the joist with rubber to make it quieter.


It must be bad though because I can hear it downstairs through 3 closed
doors.

That is bad.

Adam

[Lobster]

the_constructor wrote:
Just out of curiosity, are 12V timer fans noisier than 240V fans....?
[...]
The fan is from Screwfix....

I have one of each type at home in the two bathrooms, both cheapo
Screwfix in-line ones mounted on rafters or joists. If anything, I'd
say the 240V one was a bit noisier; may be down to less effective
mounting (the 12V one's definitely mounted on rubber pads but I can't
remember how I did the 240V one!)

David

[Andy Champ]

the_constructor wrote:
Just out of curiosity, are 12V timer fans noisier than 240V fans....?

I got a 12V fan and my neighbour nearly jumps out of her skin when it is
switched on.

I installed it correctly a few months ago but after a week I disconnected
it.

It must be bad though because I can hear it downstairs through 3 closed
doors.

The fan is from Screwfix....

James


12v fans are exactly the ones fitted in PCs. If you want quiet, look at
someone like quietpc.com and find a low noise case fan. Make sure it
isn't speed regulated though, you want a 2-wire one, and replace the one
in the unit.

A word of caution - some quiet fans are quiet just because they don't
push much air. And the one in the unit you've bought may be a high
power centrifugal unit, much better at pushing air through a duct
against an incoming wind!

I've had a case fan in a vent unit for the last 15 years or so. It's
getting a bit tired now!

Andy

[Andrew Gabriel]

In article ,
Andy Champ writes:
12v fans are exactly the ones fitted in PCs.

I only ever looked at one, a Wickes one, about 5 years ago.
That was a shaded pole induction motor, exactly the same as
the mains ones (but presumably thicker wire in the windings),
and fed via a separate 12VAC transformer. Quite different
from PC fans, which run from DC.

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

[Donwill]

"the_constructor" wrote in message
...

Just out of curiosity, are 12V timer fans noisier than 240V fans....?

I got a 12V fan and my neighbour nearly jumps out of her skin when it is
switched on.

I installed it correctly a few months ago but after a week I disconnected
it.

It must be bad though because I can hear it downstairs through 3 closed
doors.

The fan is from Screwfix....

James
I have a screwfix ceiling mounted bathroom fan that plugs into a 4ins duct
which extracts through the pine end of the bungalow. In order to reduce the
awful noise it generates, I have been looking for an externally mounted fan
which would, I believe reduce the noise level.
I have failed to find a fan in the UK but have found an American one which
would do the business if I could find an European or better still a British
agent which could supply a 240V model.
I have a link to the Fan as follows:
http://www.continentalfan.com/ext

[Andy Champ]

Andrew Gabriel wrote:
In article ,
Andy Champ writes:
12v fans are exactly the ones fitted in PCs.

I only ever looked at one, a Wickes one, about 5 years ago.
That was a shaded pole induction motor, exactly the same as
the mains ones (but presumably thicker wire in the windings),
and fed via a separate 12VAC transformer. Quite different
from PC fans, which run from DC.


:O

I stand corrected. My fan BTW is a mains one... and when did you last
see a mains case fan?

Andy

[Peter Parry]

On Sun, 24 Feb 2008 12:09:36 -0000, "the_constructor"
wrote:


I installed it correctly a few months ago but after a week I disconnected
it.

I once had to try to help sort out ventilation in an old Victorian
flat with single brick walls. For the bathroom/toilet by far the most
successful was not to use the usual high output short duration fan but
to install a small ducted fan which ran all day. It was a small
Wickes unit of about 20W consumption and was put on a timeswitch to
run from 06:00 to 22:00. It kept the bathroom mould and steam free
remarkably effectively. The only time it could be heard was in the
dead of night (hence the timeswitch). During the day it was
inaudible.

[Andrew Gabriel]

In article ,
Andy Champ writes:
Andrew Gabriel wrote:
In article ,
Andy Champ writes:
12v fans are exactly the ones fitted in PCs.

I only ever looked at one, a Wickes one, about 5 years ago.
That was a shaded pole induction motor, exactly the same as
the mains ones (but presumably thicker wire in the windings),
and fed via a separate 12VAC transformer. Quite different
from PC fans, which run from DC.


:O

I stand corrected. My fan BTW is a mains one... and when did you last
see a mains case fan?

This morning, at the Tolworth computer fair.
Several stands at the Bracknell computer fair have
been regularly selling them for a couple of years now.

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

[Andy Champ]

Andrew Gabriel wrote:
In article ,
Andy Champ writes:

I stand corrected. My fan BTW is a mains one... and when did you last
see a mains case fan?

This morning, at the Tolworth computer fair.
Several stands at the Bracknell computer fair have
been regularly selling them for a couple of years now.


I'm not doing very well here am I!

Andy

[Andrew Gabriel]

In article 47c162b8@qaanaaq,
Andy Hall writes:

- bearings and motor. This relates to the manufacturer and quality
of the product.

My experience of a few makes:

Manrose: Sleeve bearings, cease, motor burns out.

Deta: Sleeve bearings, cease, self-reseting thermal trip protects motor,
thus repairable.
(Don't think Deta exist any more. CPC used to do their range.)

Vent-axia: Haven't had one go wrong yet, so I haven't had to look inside.
Noisey (might be ball bearing -- they are not as quiet as sleeve bearings).

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

[the_constructor]

"Andy Hall" wrote in message news:47c162b8@qaanaaq...
On 2008-02-24 12:09:36 +0000, "the_constructor"
said:


Just out of curiosity, are 12V timer fans noisier than 240V fans....?

It depends.

There are several factors:

- Fan size. A larger one under-run will be much quieter than a small
one run at max setting

- axial/centrifugal. Centrifugal fans can have more throughput and are
able to move air through a long duct better than axial fans. However,
they are noisier.

- bearings and motor. This relates to the manufacturer and quality of
the product.

- mounting. A fan mounted directly to a plasterboard wall or especially
ceiling has a very good sounding board to amplify the sound.


I got a 12V fan and my neighbour nearly jumps out of her skin when it is
switched on.

I installed it correctly a few months ago but after a week I disconnected
it.

It must be bad though because I can hear it downstairs through 3 closed
doors.

The fan is from Screwfix....

Mmmm.....

Take a look at the LoWatt range from Vent Axia. I fitted one of these
in my cloakroom. It is suitable for bathrooms as well and runs from
12v. Very quiet indeed. I fitted it using rubber mounts and sealing
gasket, which reduces the sound yet further.


Can you possibly give me a ref number please ?
Can you explain difference between axial and centrifugal etc.
James

[Andy Hall]

On 2008-02-27 23:19:32 +0000, "the_constructor"
said:
Can you possibly give me a ref number please ?
Can you explain difference between axial and centrifugal etc.
James

http://www.vent-axia.com/lo-carbon/l...esidential.asp

http://www.vent-axia.com/knowledge/h...whatisafan.asp

[Palindrome]

the_constructor wrote:
snip
Can you explain difference between axial and centrifugal etc.

Axial - think boat propeller. Air comes in the front and goes out the back.

http://www.bobstevenson.co.uk/images..._axial_fan.jpg

Where this type comes into its own is when the flow needs to be capable
of being reversed.

Centrifugal - think spin drier. Air comes in at the centre and leaves at
the edge.

http://img.alibaba.com/photo/5054968...ved_Blades.jpg

Where this type comes into its own is when operating against back
pressure, eg a long delivery tube or trunking.


--
Sue

[Andy Champ]

the_constructor wrote:
Can you explain difference between axial and centrifugal etc.


See

http://en.wikipedia.org/wiki/Axial_compressor
http://en.wikipedia.org/wiki/Centrifugal_compressor


Andy

[John]

"Andy Champ" wrote in message
...
the_constructor wrote:
Can you explain difference between axial and centrifugal etc.


See

http://en.wikipedia.org/wiki/Axial_compressor
http://en.wikipedia.org/wiki/Centrifugal_compressor


Andy

Try this as well:


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

[the_constructor]

"John" wrote in message
...

"Andy Champ" wrote in message
...
the_constructor wrote:
Can you explain difference between axial and centrifugal etc.


See

http://en.wikipedia.org/wiki/Axial_compressor
http://en.wikipedia.org/wiki/Centrifugal_compressor


Andy

Try this as well:


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

Hi,
I would like to thank everyone for their input on this subject. I am really
grateful for all your help.
James