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Topic Title: Two bathrooms and one toilet - One fan
Topic Summary: Any ideas ?
Created On: 17 April 2013 07:37 AM
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 17 April 2013 07:37 AM
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SherlockOhms

Posts: 320
Joined: 05 April 2011

Chaps,

I recall a recent post on controling one fan feeding several rooms.

The problem as I see it is that of lighting ie, if the lights are switched on in one bathroom then the switched live feed to the fan will back feed all of the lights in the other rooms.

I'm sure there are ways to do it with relays, smoke and mirrors but, is there a controller available for this?

Many thanks,

S.
 17 April 2013 07:39 AM
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aligarjon

Posts: 2802
Joined: 09 September 2005

occupancy sensor in each room seperate from the light ?

Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
 17 April 2013 07:56 AM
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SherlockOhms

Posts: 320
Joined: 05 April 2011

......so the sensor would sit in the switched live of each room causing open circuit unless the room was occupied? Liking it.

Pull chords must still function as customer requires option to enter without switching lights on.

S.
 17 April 2013 08:01 AM
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dickllewellyn

Posts: 1150
Joined: 19 March 2010

That or a couple of relays controlling the fan?

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Richard (Dick)

"Insert words of wisdom and/or witty pun here"
 17 April 2013 08:41 AM
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unshockable

Posts: 840
Joined: 18 May 2007

Hi

To stop the feedback you need to use isolators in place of 1 way switches. Looking at the back of said isolator, connect the bottom 2 terminals together, this is also where the local lighting comes from.

Now you have 2 empty terminals at the top. One side is perm live in, the other is fan switch live out. If you think about this arrangement it crucially stops the feedback when the local light is off but another is switched on.

They all need to be on the same circuit and you need an extra core so run a 3 core and earth?

Simon
 17 April 2013 09:18 AM
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AJJewsbury

Posts: 11295
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Pull chords must still function as customer requires option to enter without switching lights on.

Are you saying that there are separate pull switches for the fan? In that case why not use retractive (momentary) pull switches, wired in parallel, to trigger a single timer which then controls the fan.
- Andy.
 17 April 2013 09:25 AM
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SherlockOhms

Posts: 320
Joined: 05 April 2011

Andy,

No, just separate pull chords for the lights.

S.
 17 April 2013 10:35 AM
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AJJewsbury

Posts: 11295
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No, just separate pull chords for the lights.

(I'm not 100% sure I've understood), but wouldn't the simplest thing be to swap the pull switches for DP ones (some 15A ones are DP - see http://www.tlc-direct.co.uk/Products/MK3151.html), use one pole to control the light and the other the fan. You can either wire them as Simon suggested, or connect the perm L to both supply terminals and the light and fan separately to the out terminals, or even have them on two different circuits (no link).
- Andy.
 17 April 2013 02:15 PM
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AJJewsbury

Posts: 11295
Joined: 13 August 2003

Maybe pictures would help:

One way of switching a fan with three separate lights:



or with a separate circuit for the fan (e.g. if the manufacturer demands it's fused down):



In both cases you can add a permanent line to the fan if it need a run-on timer, and a local isolator if required.

- Andy.
 17 April 2013 04:48 PM
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aligarjon

Posts: 2802
Joined: 09 September 2005

Originally posted by: SherlockOhms

......so the sensor would sit in the switched live of each room causing open circuit unless the room was occupied? Liking it.



Pull chords must still function as customer requires option to enter without switching lights on.



S.




No. completely seperate from the lights. Take the feed from one by all means but none of the lights need to be on for the fan to operate. Just fit a sensor in each room.. The lights still switch as they are.

Gary

-------------------------
Specialised Subject. The Bleedin Obvious. John Cleese
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