I am fitting an 4" extractor fan in the bathroom wired from a junction box
on the lighting circuit so does it still need a double pole isolator
switch?.

--
Trevor Smith

"Trevor Smith" wrote
| I am fitting an 4" extractor fan in the bathroom wired from a junction box
| on the lighting circuit so does it still need a double pole isolator
| switch?.

Yes, it needs an isolator for mechanical maintenance.

If you are using a run-on timer you will need a triple-pole fan isolator
switch. You might as well use one anyway, as they have a little fan symbol
on and can be locked off, which is required if they are not 'under the
control' of anyone working on the fan.

Owain

"Trevor Smith" wrote in message ...
I am fitting an 4" extractor fan in the bathroom wired from a junction box
on the lighting circuit so does it still need a double pole isolator
switch?.

If you have no external wall there you need one, but otherwise I
wouldnt bother. People often fit these in the hope it will clear
smells or damp, but really theyre fairly useless. A far more effective
alternative is a locking mechanism that allows the window to be locked
securely 1/2" open when wanted. 4" fans get noisy over time, waste
electricity, throw heat away, and are simply ineffective.


Regards, NT

"Trevor Smith" wrote in message ...
I am fitting an 4" extractor fan in the bathroom wired from a junction box
on the lighting circuit so does it still need a double pole isolator
switch?.

If you have no external wall there you need one, but otherwise I
wouldnt bother. People often fit these in the hope it will clear
smells or damp, but really theyre fairly useless. A far more effective
alternative is a locking mechanism that allows the window to be locked
securely 1/2" open when wanted. 4" fans get noisy over time, waste
electricity, throw heat away, and are simply ineffective.


Regards, NT

In message ,
(N. Thornton) wrote:

"Trevor Smith" wrote in message ...
I am fitting an 4" extractor fan in the bathroom wired from a junction box
on the lighting circuit so does it still need a double pole isolator
switch?.

If you have no external wall there you need one, but otherwise I
wouldnt bother. People often fit these in the hope it will clear
smells or damp, but really theyre fairly useless. A far more effective
alternative is a locking mechanism that allows the window to be locked
securely 1/2" open when wanted. 4" fans get noisy over time, waste
electricity, throw heat away, and are simply ineffective.


Have you had experience of humidistat control? If damp is the issue, it
should be the cure and I'm thinking of fitting one, but I completely
agree with your point about wasted heat.

As I see it there are three ways around the heat thing:

1: make sure the only air leaks into the bathroom are from the heated
part of the house - doesn't stop wasting heat (but then neither does
leaving the window open), but doesn't cool the bathroom too much;

2: use one of those rather expensive in-wall heat-exchanger things.
Looks like an ordinary 4" (or 6") from the inside and outside, but in
reality is an air exchange unit which uses the heat from the outgoing
air to pre-heat incoming air;

3: install one of those very expensive whole-house mechanical heat
recovery and ventilation systems, beloved of IMM.

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... User - a technical term used by computer pros. See idiot.

On Tue, 18 May 2004 00:58:36 +0100, in uk.d-i-y Martin Angove
strung together this:

one of those rather expensive in-wall heat-exchanger things.

They're not that expensive actually, I usually get them for about
£120ish.

Looks like an ordinary 4" (or 6") from the inside and outside,

6" usually.
--

SJW
A.C.S. Ltd.

In message ,
(Lurch) wrote:

On Tue, 18 May 2004 00:58:36 +0100, in uk.d-i-y Martin Angove
strung together this:

one of those rather expensive in-wall heat-exchanger things.

They're not that expensive actually, I usually get them for about
£120ish.

£120 is expensive when you compare it with £9.59 for a cheap 4" timer
job from Screwfix, though granted they also do a 6" Xpelair for £69.99.


Looks like an ordinary 4" (or 6") from the inside and outside,

6" usually.

I didn't really look to hard at these things because of the price
difference (I will probably fit 4" humidistat cheapies from Screwfix -
£29.99) which adds up to quite a lot if you are fitting more than one or
two, but I'm sure I saw a model which was 4", some manufacturer
beginning with "B" on a stand at the 2003 NEC H&R show.

Great idea, will have to save up for a few when we build :-)

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... Unable to locate Coffee -- Operator Halted!

Lurch wrote in message ...

etc
or
4) fit a Broan N655x heat/light/extract unit, not cheap, 110V, but heaven to
use!!

I've never seen the equivalent in the UK, I don't understand why.

Regards
Capitol

On Fri, 21 May 2004 21:37:36 +0100, in uk.d-i-y "Capitol"
strung together this:


Lurch wrote in message

No I didn't.
--

SJW
A.C.S. Ltd.

Martin Angove wrote in message ...
In message ,
(N. Thornton) wrote:
"Trevor Smith" wrote in message ...

I am fitting an 4" extractor fan in the bathroom wired from a junction box
on the lighting circuit so does it still need a double pole isolator
switch?.

If you have no external wall there you need one, but otherwise I
wouldnt bother. People often fit these in the hope it will clear
smells or damp, but really theyre fairly useless. A far more effective
alternative is a locking mechanism that allows the window to be locked
securely 1/2" open when wanted. 4" fans get noisy over time, waste
electricity, throw heat away, and are simply ineffective.

Have you had experience of humidistat control? If damp is the issue, it
should be the cure and I'm thinking of fitting one,

Well, its upto you of course. I was just saying that IME 4" fans are
rubbish at controlling damp.

but I completely
agree with your point about wasted heat.

As I see it there are three ways around the heat thing:

1: make sure the only air leaks into the bathroom are from the heated
part of the house - doesn't stop wasting heat (but then neither does
leaving the window open), but doesn't cool the bathroom too much;

The advantage with the window option is that it uses no lectricity, is
silent, and will last a lifetime. Yes you still lose heat: a
dehumidifier is the only way to not lose heat.


2: use one of those rather expensive in-wall heat-exchanger things.
Looks like an ordinary 4" (or 6") from the inside and outside, but in
reality is an air exchange unit which uses the heat from the outgoing
air to pre-heat incoming air;

3: install one of those very expensive whole-house mechanical heat
recovery and ventilation systems, beloved of IMM.

I'd consider putting a dehumidifier in the room. Cheaper than £120, no
heat lost. Be sure to observe the extra wiring requirements for
electricals in a bathroom.


Regards, NT

In message ,
(N. Thornton) wrote:

Martin Angove wrote in message ...
In message ,
(N. Thornton) wrote:
"Trevor Smith" wrote in message ...

I am fitting an 4" extractor fan in the bathroom wired from a junction box
on the lighting circuit so does it still need a double pole isolator
switch?.

If you have no external wall there you need one, but otherwise I
wouldnt bother. People often fit these in the hope it will clear
smells or damp, but really theyre fairly useless. A far more effective
alternative is a locking mechanism that allows the window to be locked
securely 1/2" open when wanted. 4" fans get noisy over time, waste
electricity, throw heat away, and are simply ineffective.

Have you had experience of humidistat control? If damp is the issue, it
should be the cure and I'm thinking of fitting one,

Well, its upto you of course. I was just saying that IME 4" fans are
rubbish at controlling damp.


[...]

I'd consider putting a dehumidifier in the room. Cheaper than £120, no
heat lost. Be sure to observe the extra wiring requirements for
electricals in a bathroom.


Mmm... but under what circumstances? A 4" on a 10 minute run-on timer
isn't going to shift any appreciable amount of humidity from anything
except the smallest bathroom, but unless the room is very large or the
installation very leaky (so that air is short-circuited around the fan)
surely a humidity controlled fan would work, eventually? At £30 and
requiring nothing more than a DP switch from the lighting circuit it's
a bit cheaper and easier to install and maintain than a dehumidifier
too.

As you say, personal preference, though in my case budget counts for
a lot too :-)

Hwyl!

M.

--
Martin Angove: http://www.tridwr.demon.co.uk/
Two free issues: http://www.livtech.co.uk/ Living With Technology
.... I'm no stranger, just a friend you haven't met...

Martin Angove wrote in message ...
In message ,
(N. Thornton) wrote:
"Trevor Smith" wrote in message ...

I am fitting an 4" extractor fan in the bathroom wired from a junction box
on the lighting circuit so does it still need a double pole isolator
switch?.

If you have no external wall there you need one, but otherwise I
wouldnt bother. People often fit these in the hope it will clear
smells or damp, but really theyre fairly useless. A far more effective
alternative is a locking mechanism that allows the window to be locked
securely 1/2" open when wanted. 4" fans get noisy over time, waste
electricity, throw heat away, and are simply ineffective.

Have you had experience of humidistat control? If damp is the issue, it
should be the cure and I'm thinking of fitting one,

Well, its upto you of course. I was just saying that IME 4" fans are
rubbish at controlling damp.
[...]

I'd consider putting a dehumidifier in the room. Cheaper than £120, no
heat lost. Be sure to observe the extra wiring requirements for
electricals in a bathroom.


Mmm... but under what circumstances? A 4" on a 10 minute run-on timer
isn't going to shift any appreciable amount of humidity from anything
except the smallest bathroom, but unless the room is very large or the
installation very leaky (so that air is short-circuited around the fan)
surely a humidity controlled fan would work, eventually? At £30 and
requiring nothing more than a DP switch from the lighting circuit it's
a bit cheaper and easier to install and maintain than a dehumidifier
too.

As you say, personal preference, though in my case budget counts for
a lot too :-)


The basic problem is that it doesnt work.

The secondary problems are noise, energy waste due to run power plus
throwing all your warm air away several times over, which is the only
way these could ever dry the room out.


Regards, NT