Hi, in my cloakroom I have a light and extractor fan ( no windows ),
the fan has a run on of a few minutes after the light switch is turned
off which is fine and alll works dandy. The issue is that the switch
for the cloakroom is on the outside, which again is fine but what
tends to happen is that they switch on the light first, enter the room
do their business and then close the door leaving the light and hence
the fan on. It can be quite some time before someone realises that the
light is still on - wasting power and melting ice caps etc.....

I was in B&Q the other day and saw a neat little timer delay switch
with touch control, looked exactly what I was after, replaces a normal
light switch, did a soft start of the light and remained on for a
configurable number of minutes before switching off. I bought one of
these and fitted it, all seemed ok, nice soft start of the halogen
lamps and fan came on. after 5 minites light went off and fan remained
on as I'd expected. What I did not expect however is that the fan
just stayed on! and didnt go off at all even after the normal run on
time had well elapsed.

I had to remove the switch an revert back to the old one.

Can someone please advice what is going on here and also what the
solution should be - apart from putting the switch in the room...

regards

Nigel

Nigel wrote:

Can someone please advice what is going on here and also what the
solution should be - apart from putting the switch in the room...

This is a common problem with anything "clever" designed to replace a
light switch. Because switch positions are typically not wired with a
neutral, there is no easy way for electronic switch gizmos to draw
power, other than by "leaking" a small amount of current through the
bulb. This can cause a couple of problems; like those you are seeing. It
can also break with non incandescent bulbs.

--
Cheers,

John.

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Your solution on this would be to replace the fan with a non timer
fan. I dont know if you could even get away with just removing the
constant supply wires from your existing one so that it is only being
fed directly from the lights supply. No doubt someone will help with
this. My gut feeling is that by simply removing the constant feed that
this will solve the problem.

Be aware though that even with the light switched off, there will
still be a live cable at your fan, so I would advise turning off your
electrics before doing this job, and then just putting terminal blocks
to isolate the cables that you remove. If at all in doubt with your
electrics then call out an electrician. If you feel competent then
keep the electricity turned on, put your old switch in. Put it in the
off position and then use a multimeter to ascertain which cable/s are
the constant feeds.

Good luck and stay safe
Calum Sabey
NewArk Traditional Kitchens 01556 690544

wrote:

Your solution on this would be to replace the fan with a non timer
fan. I dont know if you could even get away with just removing the

Might not be so good as the room has no other ventilation by the sounds
of it.


A mechanical version of the switch would not exhibit the same problem:

http://www.tlc-direct.co.uk/Products/EK400A.html


--
Cheers,

John.

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On 27 Feb 2007 12:40:47 -0800 someone who may be "Nigel"
wrote this:-

Hi, in my cloakroom I have a light and extractor fan ( no windows ),
the fan has a run on of a few minutes after the light switch is turned
off which is fine and alll works dandy. The issue is that the switch
for the cloakroom is on the outside, which again is fine but what
tends to happen is that they switch on the light first, enter the room
do their business and then close the door leaving the light and hence
the fan on. It can be quite some time before someone realises that the
light is still on - wasting power and melting ice caps etc.....

Replace the switch with a gridswitch plate with two spaces. In one
space of the gridswitch fit a switch, in the other fit a neon
indicator which comes on when the light is energised.
http://www.mkelectric.co.uk/products...p?RangeID=1026

Alternatively switches with neon indicators built in are available.

I was in B&Q the other day and saw a neat little timer delay switch
with touch control, looked exactly what I was after, replaces a normal
light switch, did a soft start of the light and remained on for a
configurable number of minutes before switching off.

A good way of getting people to only pay quick trips I suppose.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

Replace the switch with a gridswitch plate with two spaces. In one
space of the gridswitch fit a switch, in the other fit a neon
indicator which comes on when the light is energised.
http://www.mkelectric.co.uk/products...p?RangeID=1026

Alternatively switches with neon indicators built in are available.


A good way of getting people to only pay quick trips I suppose.

Neon indicators usually need a neutral to work if "illuminated when
on" is required.

I have a similar problem of people leaving the bathrrom ligh(and fan)
on and am resigned to pulling a neutral feed through to switch.

There dont appear to be any lowcost or unobtrusive PIR switches
around.
Robert

lid wrote:

There dont appear to be any lowcost or unobtrusive PIR switches
around.

http://www.tlc-direct.co.uk/Main_Ind...tch/index.html

--
Cheers,

John.

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Nigel
I still stick by my 1st suggestion of removing the timer element of
the fan (via one of the 2 methods mentioned). The fact that you now
have a timer switch means that John's argument against disabling the
timer is not valid. I am assuming that you will set the timer so the
light and fan go off about 10 minutes after the person enters the
room.
Calum Sabey

On Wed, 28 Feb 2007 17:46:20 +0000 someone who may be
lid wrote this:-

Neon indicators usually need a neutral to work if "illuminated when
on" is required.

While that is best I'm not convinced that a low current through the
protective conductor is a great problem. It might be if electric
supplies were DC, as that could lead to high resistance joints being
formed.


--
David Hansen, Edinburgh
I will *always* explain revoked encryption keys, unless RIP prevents me
http://www.opsi.gov.uk/acts/acts2000/00023--e.htm#54

On Wed, 28 Feb 2007 21:52:07 +0000, John Rumm
wrote:

wrote:

There dont appear to be any lowcost or unobtrusive PIR switches
around.

http://www.tlc-direct.co.uk/Main_Ind...tch/index.html

Thanks for link but no good for in bathroom - though I suppose I
could mount it in the ceiling with just PIR showing through hole.
Robert

lid wrote:
On Wed, 28 Feb 2007 21:52:07 +0000, John Rumm
wrote:

lid wrote:

There dont appear to be any lowcost or unobtrusive PIR switches
around.
http://www.tlc-direct.co.uk/Main_Ind...tch/index.html

Thanks for link but no good for in bathroom - though I suppose I
could mount it in the ceiling with just PIR showing through hole.

Why do you say it is no good for a bathroom? So long as it can be placed
in zone three it ought to be fine.


--
Cheers,

John.

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