wiring in a bathroom extractor

[Robbox]

What I'd like to do, but don't know if possible, is have the fan and lights on one switch but have the fan only come on when the humidity goes above the threshold. I know a lot of bathrooms have it so the fan comes on irrespective. But we do have an opening window light in the room.
My builder tells me that humidistat fans are easily affected by outside conditions and can come on when you don't want. The bathroom outside wall does get the brunt of storms that pass through.

 

[AndyPRK]

well you could have a manrose fan with inbuilt humidity sensor.

If you don't want it coming on with the light (to remove smells) then don't connect the switched wire up. And it will work automatically.

It's true humidistat fans do take a lot of adjusting to get spot on

 

[ban-all-sheds]

Why not just buy a fan which you turn on and off as and when it is needed?

What is the underlying functionality re when you want the fan to come on?

 

[Robbox]

Why not just buy a fan which you turn on and off as and when it is needed?

What is the underlying functionality re when you want the fan to come on?

I guess to have the fan running without human intervention, people can be forgetful...especially kids!

 

[JohnD]

modern extractors can be near-silent and use negligible amounts of electricity.

What are the benefits you foresee from preventing the fan starting when the bathroom is used?

 

[ban-all-sheds]

I guess to have the fan running without human intervention, people can be forgetful...especially kids!

What is the underlying functionality re when you want the fan to come on?

 

[mattylad]

I think the underlying functionality is for it to spin and remove smells and steam
Anything else is a bonus.,

 

[EFLImpudence]

I think (might be wrong) Bas just means - how does the OP want the fan to operate?, because -

What I'd like to do,..., is have the fan and lights on one switch but have the fan only come on when the humidity goes above the threshold.

That means he doesn't want it to operate to remove smells nor, indeed, when the humidity is still high but the light has been turned off - which seems not ideal.

 

[ban-all-sheds]

I think the underlying functionality is for it to spin and remove smells and steam
Anything else is a bonus.,

I sometimes wonder if I've stumbled into a parallel universe where it looks as if everybody speaks English, but they don't.

What is the underlying functionality re when you want the fan to come on?

 

[AndyPRK]

I think the key word in the sentence is ON.

I'm surprised Ban hasn't underlined it.

What do the kids forget to do? Do they forget to turn it ON ?
Do they forget to turn it OFF ?

When do you want it to come ON ? and go off ?

 

[ban-all-sheds]

I think the key word in the sentence is ON.

I'm surprised Ban hasn't underlined it.

No need - you have at last seen it.

What do the kids forget to do? Do they forget to turn it ON ?

Possibly.

Do they forget to turn it OFF ?

Possibly.

When do you want it to come ON ?

That's what I keep asking.

 

[JohnD]

Let's postulate that a bathroom extractor is required under the following circumstances:

When the WC has been used

When the bath has been used

When the shower has been used.

When a flatulent plumber has been in the bathroom.

Let's postulate that it is not required when none of these conditions has been satisfied.

Does anyone know what hardship will be caused if the fan starts needlessly, when a person walks into the bathroom to admire the tiling?

 

[Robbox]

OK guys...I get it...I'll go crawl back under my rock.

 

[AndyPRK]

well, just answer the question and we will be glad to help.

 

[ban-all-sheds]

It is a bit like pulling teeth....

have the fan only come on when the humidity goes above the threshold

What makes the humidity rise to the point where you want a extractor fan to operate?