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Topic Title: Bathroom fan
Topic Summary: Dimmer/rela control?
Created On: 26 January 2013 06:54 PM
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 26 January 2013 06:54 PM
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SherlockOhms

Posts: 322
Joined: 05 April 2011

Evening all,

Client would like her new LED downlighters in the bathroom dimmed.

I've searched most of the related posts here but I can't seem to find a definitive answer as to whether or not the electronics of a fan will object to a reduced switched live voltage?

If this is the case then it's simple enough to add in a relay using the switched live to drive the coil, the contacts providing a switched live unaffected by the dimmer control.

The question here is what is the drop out voltage of the relay relative to the output of a fully dimmed dimmer or, to further complicate matters, will the relay pull in if the dimmer is set to dim when switched on? Maybe it will work perfectly and drop out the fan at a certain lighting level?

I do recall a recent post about a dimmer switch brand with a separate non dimmed output. This I guess will require a three core at least to the switch?

Perhaps the simple answer is to add a separate pull switch for the fan,
after all, when wanting the lights dim (ambient bath mode) it's unlikely she'll want a fan whirring away in the background spoiling the mood?

Thanks in advance,

S.
 26 January 2013 09:33 PM
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DOUGIE1000

Posts: 4164
Joined: 13 August 2005

http://www.theiet.org/Forums/f...=50291&highlight_key=y

Someone must make a leading edge version

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 26 January 2013 09:35 PM
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DOUGIE1000

Posts: 4164
Joined: 13 August 2005

What about humidistat automatic fan?

-------------------------
Dougie
Power Plus Electrical.co.uk

My mission is to live as long as possible......so far so good!
 26 January 2013 10:49 PM
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primo

Posts: 434
Joined: 10 January 2008

See HERE where I tried to do the same thing.

As the dimmer was turned down the relay started dropping in and out rapidly and loudly!

It does depend on the fan though. Ive installed dimmers with bathroom fans before and the fan will activate until the dimmer gets at least half way down, this has been with Vent Axia fans.

It is the Airflow Quiet Air fans that won't activate at all via a dimmer.
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