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

[telectrix]

Until the technology advances to the point when an open window flows air in one direction only, I'll stick with an extractor fan for at least six months of the year.

simples solution. increase the pressure inside the barthroom/bog so that the airflow is to the outside. a few good farts should sudfice.

 

[brianmoooore]

The 'few good farts' are a major part of the problem, according to my missus.

 

[telectrix]

The 'few good farts' are a major part of the problem, according to my missus.

well, it's just jealosy. women can't fart as much as they can't keep their gobs shut long enough to build up the necessary pressure.

 

[Mike Johnson]

The Manrose remote Humidistat will work even if the light is off, a light can be wired across the off side of the single switch and mains neutral: https://myshop.s3-external-3.amazon...mages.Ventilator-vochtsensor-elektronisch.pdf

 

[LastManOnline]

. a few good farts should sudfice.

I was afraid he had retired? Been missed.
Any disquite about Tel,s state of health can now be fully dismissed.I,m not sure what type of barometer the hospital staff used to gauge his recovery ,but readers on here always knew that when he once again would discuss with gusto the topic closest to his heart (no pun intended.And no ,its not electrics), that we could state with confidence "He,s back!.Normal service has resumed"

 

[telectrix]

still here. new laptop as windoze no longer supporst window 7. buggers. got to get it all working. and as regards my state of health. getting better day by day. long as i caN DRIVE TO THE LOCAL SPAR FOR BEER AND smokes.......

 

[MisterProzilla]

The Manrose remote Humidistat will work even if the light is off, a light can be wired across the off side of the single switch and mains neutral: https://myshop.s3-external-3.amazon...mages.Ventilator-vochtsensor-elektronisch.pdf

That's the exact remote humidistat I bought thinking it should be able to work, as you say, even when the light is off.

I queried it with the electrician - he says that the fan will always work with the light regardless, then run on, until humidity is gone.
I don't know, maybe my expectations were back to front about how they actually work - I thought they woul detect moisture THEN come on, rather than having to be turned on then use the stat to turn itself off. If that's the case then this remote stat is doubly redundant - no point in having the sensor if you have to turn it on manually anyway, and then no point in having the run-on timer if it's going to use the sensor to decide when to turn off.

 

[nicebutdim]

That's the exact remote humidistat I bought thinking it should be able to work, as you say, even when the light is off.

I queried it with the electrician - he says that the fan will always work with the light regardless, then run on, until humidity is gone.
I don't know, maybe my expectations were back to front about how they actually work - I thought they woul detect moisture THEN come on, rather than having to be turned on then use the stat to turn itself off. If that's the case then this remote stat is doubly redundant - no point in having the sensor if you have to turn it on manually anyway, and then no point in having the run-on timer if it's going to use the sensor to decide when to turn off.

The humidistat is a switch that operates when set humidity threshold is crossed.

The humidistat you have bought can be wired through a light switch, to operate when light is switched on and continue to run until overrun timer setting has passed. If set humidity threshold is exceeded it will continue to run until such times as humidity decreases below set threshold.

The above is dependant on a permanent live supply to stat, alongside switched live feed to light. Without that permanent supply, the fan is isn't going to run when the light is switched off.

It is equally possible to wire the stat through a switch completely independant of lighting.

Please note that manufacturer specification for your stat stipulates that it must be fused at a maximum of 3A and wired through double pole isolation (3 pole if wired through lighting).

 

[Mike Johnson]

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.

 

[nicebutdim]

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.

Read through the OP.

 

[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.