Replacing a bathroom extractor fan

[statstastic]

I have an internal, windowless toilet with an extractor fan. The fan is wired into the lighting circuit and comes on and off with the light (no timer).

I'm having a shower added to this room so want to replace the fan with one with a humidistat and timer. Can I simply replace the fan or does a humidistat timer need a separate supply of power? Do they have an internal battery to store power when the light is turned off?

 

[JohnW2]

I have an internal, windowless toilet with an extractor fan. The fan is wired into the lighting circuit and comes on and off with the light (no timer). I'm having a shower added to this room so want to replace the fan with one with a humidistat and timer. Can I simply replace the fan or does a humidistat timer need a separate supply of power? Do they have an internal battery to store power when the light is turned off?

If you simply replaced it, neither the humidistat or the timer would be able to turn the fan on when the light was off. To get such functionality, the humidistat/timer fan would have to be supplied with a 'permanent live' as well as (if you wanted it also to be light-controlled) the 'switched live' from the light. Do I take it that the supply to your present fan just has two wires (maybe plus earth) - red/black or brown/blue?

Kind Regards, John

 

[ban-all-sheds]

Unless you want the fan to come on whenever you use the room, i.e. not only when the shower is used, I strongly advise taking the opportunity of a shower being installed to have it triggered by that.

There are a number of ways of doing it - what sort of shower is it?

 

[JohnW2]

Unless you want the fan to come on whenever you use the room, i.e. not only when the shower is used, I strongly advise taking the opportunity of a shower being installed to have it triggered by that.

Given that it's a windowless toilet, I would suspect that the OP might well want it to "come on whenever he uses the room". Indeed, regulations would require that (and a run-on timer) if it were 'new'.

Kind Regards, John

 

[ban-all-sheds]

True - he does say he's having a shower added, not that it's being converted into a shower.

 

[EFLImpudence]

Given that it's a windowless toilet, I would suspect that the OP might well want it to "come on whenever he uses the room". Indeed, regulations would require that (and a run-on timer) if it were 'new'.

Does anyone know why the regulations demand this?

What difference does it make to the powers that be if your toilet remains smelly for a fraction longer or the smell travels outside the room?

Why don't they mandate that if there is a window it must be opened?

 

[JohnW2]

Does anyone know why the regulations demand this? ... What difference does it make to the powers that be if your toilet remains smelly for a fraction longer or the smell travels outside the room?

What difference does it make to the PTB if your house is cold, damp, 'inefficient' or whatever, even 'electrically (or otherwise) unsafe'? Nanny (or, perhaps, more topical, Big Brother) has taken control of the regulations.

Why don't they mandate that if there is a window it must be opened?

That, of course, is the thing which makes the regulation incredibly daft. If the regulation exists because of a perceived potential health issue (or something else equally 'important'), they ought to demand extractors whether there is an 'openable' window or not (or perhaps some alternative 'automatic window opening' gizmo!!). They would also need to think about how they would ensure that the extractor came on when the room was used during daylight hours, if it had an unopenable (or unopened) window!

Kind Regards, John

 

[statstastic]

If you simply replaced it, neither the humidistat or the timer would be able to turn the fan on when the light was off. To get such functionality, the humidistat/timer fan would have to be supplied with a 'permanent live' as well as (if you wanted it also to be light-controlled) the 'switched live' from the light. Do I take it that the supply to your present fan just has two wires (maybe plus earth) - red/black or brown/blue?

Kind Regards, John

Indeed, I want the fan to come on with the light for toilet use and to stay on with the timer or humidistat when the shower is used. It sounds like the 'permanent live' is what's needed. There are currently 3 wires going into the current fan.

 

[JohnW2]

Indeed, I want the fan to come on with the light for toilet use and to stay on with the timer or humidistat when the shower is used.

OK, but the fan would then inevitably stay on for the timed period after the light was switched off, as well as after activation by the humidistat.

It sounds like the 'permanent live' is what's needed. There are currently 3 wires going into the current fan.

Indeed. When you say "3 wires", what do you mean - 2 and an earth, or what? Is it (round) flexible cable or (flat) house-wiring cable (with bare earth)? What colours are the 3 wires?

Kind Regards, John

 

[statstastic]

Untitled

• statstastic
• 15 May 2015
• 1

Thanks, John. The wire (flat house wiring) runs in the ceiling down the ( now removed) toilet wall on the left, into the switch - where it then comes out as round cable - back behind the plywood service channel and then out again where it was attached to the fan ( now removed). The wires in the ceiling are red, blue, yellow. They change to brown, blue, green between the switch and the fan.

I'm happy for the fan to be on a 2 minute timer every time the toilet is used and for the humidistat to control the fan when the shower is used.

 

[ban-all-sheds]

What difference does it make to the PTB if your house is cold, damp, 'inefficient' or whatever, even 'electrically (or otherwise) unsafe'?

Err... how about general public health and therefore general (avoidable) demands on the public purse? Should we abandon immunisation requirements which are in place because we want herd immunity?

Personally I can see nothing but goodness in the state legislating minimum standards for a safe and healthy housing stock. I'm surprised to learn that you want developers to be able to put up housing which will harm or even kill people.

Nanny (or, perhaps, more topical, Big Brother) has taken control of the regulations.

But inevitably there will always be the loony fringe of rabid anti-government nutcases who regard total anarchy as the ideal way to organise society. Will you be leaving us soon to join the Branch Davidian Revival movement in the USA?

That, of course, is the thing which makes the regulation incredibly daft. If the regulation exists because of a perceived potential health issue (or something else equally 'important'),

I wonder if you truly realise what putting important in quotes when applied to health issues actually says about you, and your attitude to things which affect people's health?

they ought to demand extractors whether there is an 'openable' window or not (or perhaps some alternative 'automatic window opening' gizmo!!).

Or maybe the regulation is there so that people can't be saddled with bathrooms where they have no ability to ventilate them if they want to?

Or is that not jackbooted-big-brother-nanny-state-oppression-conspiracy enough for you?

 

[ban-all-sheds]

The wires in the ceiling are red, blue, yellow.

Red, blue, yellow and bare earth, surely?

They change to brown, blue, green between the switch and the fan.

Green?

Really?

 

[ban-all-sheds]

OK, but the fan would then inevitably stay on for the timed period after the light was switched off, as well as after activation by the humidistat

Depending on the shower type, there may be a way to have a basic on/off fan run when the lights are on, and have no overrun, and to overrun when the shower is used.

But I got no answer when I asked what sort of shower it is.

 

[JohnW2]

What difference does it make to the PTB if your house is cold, damp, 'inefficient' or whatever, even 'electrically (or otherwise) unsafe'?

Err... how about general public health and therefore general (avoidable) demands on the public purse? Should we abandon immunisation requirements which are in place because we want herd immunity?

What (in the UK) is this mandatory immunisation requirement that you are suggesting might be abandoned? Offering, and strongly encouraging the take-up of, immunisation is highly desirable. Requiring immunisation would be something very different, and is strongly opposed every time it is suggested. Making people aware of the ways of avoiding cold, damp, inefficient or 'unsafe' homes is again highly desirable - but, also again, requiring people to exercise those avoidances is something rather different.

That, of course, is the thing which makes the regulation incredibly daft. If the regulation exists because of a perceived potential health issue (or something else equally 'important'),

I wonder if you truly realise what putting important in quotes when applied to health issues actually says about you, and your attitude to things which affect people's health?

You are totally misreading that. Things which have a major detrimental effect on people's health are genuinely very important, without any quotes. "Something elses" which some people perceive as being 'equally important' as are threats to health probably are usually not as important (as threats to health) - hence the quotes.

Kind Regards, John

 

[JohnW2]

OK, but the fan would then inevitably stay on for the timed period after the light was switched off, as well as after activation by the humidistat

Depending on the shower type, there may be a way to have a basic on/off fan run when the lights are on, and have no overrun, and to overrun when the shower is used.

There may be - but the OP was asking about a humidistat+timer fan, and I don't think one could achieve the functionality you mention with such a fan, no matter what type of shower, could one?

Kind Regards, John