Does Extractor fan have to come on with the lights ?

stevebamford · 2 Oct 2009

Hi All,

Do I need to connect a bathroom extractor fan so it comes on automatically with the lights ? I was thinking of using a double switch so we could switch on the light only (if not using the shower)

Cheers

Steve

Paul_C · 2 Oct 2009

No, although it's become a common method there's absolutely no reason why the fan needs to be switched with the light.

Having it controlled from a completely separate switch is far more sensible, in my opinion.

stevebamford · 2 Oct 2009

Thanks - would stop the missus complaining about the noise of the fan !

Can I connect the fan switch feed directly off the light switch - was planning a 2 gang switch - this is located outside the bathroom door

ban-all-sheds · 2 Oct 2009

Yes, you can do that.

Where will you get the neutral from?

stevebamford · 2 Oct 2009

Thanks guys

Final question (for now

) - do you have any suggestions for an in-line extractor fan / shower light ?

I was looking at this one

http://www.screwfix.com/prods/25652...-Kit-100mm;jsessionid=5TCIKZS4ECAIWCSTHZPCFFI

or this one

http://www.screwfix.com/prods/32488...s/Manrose-Shower-Light-Extractor-Fan-Kit125mm

Thanks for the help

Steve

stem · 2 Oct 2009

stevebamford said:
Hi All,

Do I need to connect a bathroom extractor fan so it comes on automatically with the lights ? I was thinking of using a double switch so we could switch on the light only (if not using the shower)

Cheers

Steve

You don't say, but if your bathroom doesn't have a window and contains a WC, it should work with the light and have a 15 minute run on. If it does have a window all of the above is OK.

stevebamford · 2 Oct 2009

Cheers - bathroom does have a window

Shower-room doesn't

ericmark · 2 Oct 2009

In Part F1 Dwellings under Table 1.5 Controls for ventilation devices it states:-

For a room with no openable window (i.e. an internal room), the fan should have a 15 minute over-run. In rooms with no natural light, the fans could be controlled by the operation of the main room light switch.

From this I would think where there is natural light then some other form is required.

It does state the fan can be controlled manual or automatic so either a simple switch or a PIR would be required.

Until I looked for you I had missed the bit about natural light Upps!

Paul_C · 2 Oct 2009

stem said:
You don't say, but if your bathroom doesn't have a window and contains a WC, it should work with the light and have a 15 minute run on. If it does have a window all of the above is OK.

There's nothing to say that the fan should or must work in conjunction with the light anyway. That and the 15-minute overrun is a merely a suggestion in Approved Document Part F. And even that suggestion applies only if there is no openable window and no natural light into the room.

Discussed here recently:
//www.diynot.com/forums/viewtopic.php?p=1316476#1316476

Where will you get the neutral from?

Depends entirely upon the existing wiring layout and how much is being replaced/retained, surely?

If there's an existing ceiling fitting which is to be retained and is wired loop-in method, just run the cable to the new fan from the light location and replace the existing switch drop with a 3+E. Put an FCU in line with the fan feed somewhere, if required.

Steve · 3 Oct 2009

You have to bear in mind, if the missus complains about the noise, and you give her the ability to turn it off easily, she will NEVER turn it on, and you WILL get damp.

ban-all-sheds · 3 Oct 2009

There's nothing wrong with the missus making you damp in the bathroom..

Paul_C said:
Where will you get the neutral from?

Click to expand...

Depends entirely upon the existing wiring layout and how much is being replaced/retained, surely?

It depends on all sorts of things, but I was asking the OP, as he's the one deciding what cables to run where.

Paul_C · 3 Oct 2009

ban-all-sheds said:
It depends on all sorts of things, but I was asking the OP, as he's the one deciding what cables to run where.

Ah O.K. I think I read your question the wrong way before.

stem · 5 Oct 2009

Paul_C said:
There's nothing to say that the fan should or must work in conjunction with the light anyway

The OP asked for advice If the fan should operate automatically with the light, or manually. (no mention of other methods such as PIR) So the advice is, with the light.

Paul_C said:
The 15-minute overrun is a merely a suggestion in Approved Document Part F.

Doesn't make it bad advice, the end result still has to be achieved somehow, see below from the govenments planning portal.

"Status of Approved Documents
The Approved Documents are intended to provide guidance for some of the more common building situations. However, there may well be alternative ways of achieving compliance with the requirements. Thus there is no obligation to adopt any particular solution contained in an Approved Document if it is preferred to meet the relevant requirement in some other way.
They are given legal status by the Building Act 1984."

Paul_C · 5 Oct 2009

Thus there is no obligation to adopt any particular solution contained in an Approved Document if it is preferred to meet the relevant requirement in some other way.

Which is what I said: There is no obligation to follow any of the suggestions in the Approved Document anyway, whether they suggest linking the fan to the light or not in any given set of circumstances.

For what it's worth, however, here's the entire applicable section from Approved Document Part F:

Mechanical intermittent extract

Intermittent exctract may be operated manually and/or automatically by a sensor (e.g. humidity sensor, occupancy/usage sensor, detection of moisture/pollutant release). Humidity controls should not be used for sanitary accommodation as odour is the main pollutant.

In kitchens, any automatic control must provide sufficient flow during cooking with fossil fuels (e.g. gas) to avoid the build up of combustion products.

Any automatic control must provide manual over-ride to allow the occupant to turn the extract on.

For a room with no openable window (i.e. an internal room), the fan should have a 15 minute over-run. In rooms with no natural light, the fans could be controlled by the operation of the main room light switch.

So even if the contents of this document were compulsory, which of course they are not, it still doesn't say anything about the fan being linked to the light beyond a vague suggestion that you could do that.

stevebamford · 23 Oct 2009

Hi guys, just wanted to say thanks for your help.

The ensuite has no windows so the fan will be set up to come on with the lights

The bathroom has a whacking great street light outside so no need to turn the light on separately - so i may as well wire the fan up also with the lights as there is no real need to turn on the light at night anyway

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Does Extractor fan have to come on with the lights ?

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