Help with wiring bathroom extractor fan/old humidistat

9 Jun 2010
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United Kingdom
Hi all,

I'm redoing my shower room at the moment and one thing I need to sort/upgrade is the bathroom extractor fan and humidistat which is ancient. I have a switch that was mounted on a backbox, in the room itself. Then I have a separate humidistat, which controls the fan. The switch in the picture turns it all on/off rather than being controlled by the light switch.

It would appear that bathroom extractor fans now have the humidistat built in so presumably this is the way to go. In order to 'delete' the humidistat do I just use a wago connector or similar to connect up the live and the neutral wires that are connected to the humidistat? Furthermore should the main switch not be outside of the shower room?


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The Manrose T12 box in your picture is a 12 volt transformer with timer. It also has a pull switch for an over-ride. I don't think it is a humidity detector.

You need to look carefully at the set up. Someone installed an ELV (ie 12volt) fan for a reason. Maybe the fan is inside one of the restricted bathroom zones. So you may be stuck with a 12v fan, not a mains one.

The switch can be inside the bathroom, again, it depends on where in the bathroom it is situated with respect to the position of a bath or shower.

A diagram of the layout is the next thing.
ah right, thanks both. Didn't realise you could get 12v and 240v extractor fans and it is indeed a transformer, having a closer look (albeit is a humidity sensor as well).

Think I will get rid of it and just go for a 240v extractor (suitably rated for zone 1)
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