Bathroom fan: do UK regs require connecting via lighting circuit?

[Mike Johnson]

Read through the OP.

Read post 27 it's not working with humidity only, wired the correct way if will turn on the fan if the humidity rises above the set threshold no matter if the light is on or off, probably the humidistat is set too high for it to operate, turning the setting screw should turn on the fan at the lower end without the light.

 

[nicebutdim]

Read post 27 it's not working with humidity only, wired the correct way if will turn on the fan if the humidity rises above the set threshold no matter if the light is on or off, probably the humidistat is set too high for it to operate, turning the setting screw should turn on the fan at the lower end without the light.

Quite possible that it is set too high. When I first fitted one in my own home, humidity was an unknown quantity and a quick search of google saw all manner of reccomendations, most of which involved a fairly high humidity setting due to our often damp weather. In the end I set it as low as possible (think manufacturer's instructions state this was around 60%) and was pleased with how it worked. Timer is set to around 15 min for those times when humidity is low, but humidistat switches on and off exactly as one might expect and you can pretty much predict when humidistat will switch the fan.

 

[Mike Johnson]

I recently re-fitted our shower room and put in the a Manrose remote humidistat, whilst working in the shower room the fan would turn on just purely from perspiration without the light inside the shower being on, room lights on a separate circuit, if I remember correctly I have ours set to 40%.

 

[nicebutdim]

I recently re-fitted our shower room and put in the a Manrose remote humidistat, whilst working in the shower room the fan would turn on just purely from perspiration without the light inside the shower being on, room lights on a separate circuit, if I remember correctly I have ours set to 40%.

Can't be certain about specific humidity, but 60% sticks in my mind.

 

[Mike Johnson]

The settings on the Manrose are from 20% to 90%, I would imagine at 90% it would be permenatley on.

 

[nicebutdim]

Just checked manufacturer's data for the fans I've used and humidity can be set between 60 and 90. 60 seemed realistic and achievable in our climate.
The 20% option you have must be for customers in desert regions.

At 90% the fan would rarely come on, unless the room was filled with steam.

 

[Mike Johnson]

I got that the wrong way around, yes the 20% setting according to Manrose is always on, sorry if that confused anyone.

 

[MisterProzilla]

Read post 27 it's not working with humidity only, wired the correct way if will turn on the fan if the humidity rises above the set threshold no matter if the light is on or off, probably the humidistat is set too high for it to operate, turning the setting screw should turn on the fan at the lower end without

I got that the wrong way around, yes the 20% setting according to Manrose is always on, sorry if that confused anyone.

That humidistat will switch on whenever the humidity reaches or exceeds the threshold set on the dial irrespective of the light on or off, just turn the humidistat dial down until it comes on, you probably have it set too high.

Well, looks like that was it; turned the humidity threshold down to about 50% and the fan comes on without the light!

In my defence, I'm not always this dumb, honestly! The wiring via the lighting circuit thing threw me

Thanks for your help everyone

 

[nicebutdim]

I got that the wrong way around, yes the 20% setting according to Manrose is always on, sorry if that confused anyone.

Had me doubting myself and had to think twice before posting

 

[Mike Johnson]

Had me doubting myself and had to think twice before posting

That's what I did not do.