Replacement extractor fan with timer

[JohnW2]

A switched fan (which otherwise operates on a timed overrun) that can be independently turned off will reduce noise, particularly at night (there is a toilet in the same room).

I'm not surely that I fully understand the logistics of what your plan. If the fan usually comes on with the light (and with a timed over-run), at night you would have to find a way of turning off the isolator before turning on the lights (otherwise your noisy fan would come on, at least briefly, and wake people up) - and you would then have to remember to turn the isolator back on again (after turning off the light) in order for it to return to light-switch-activated functionality. Sounds a bit complicated (impractical?).

Kind Regards, John

 

[EFLImpudence]

Isn't he talking about a pull cord - which could be (re)wired to turn it off permanently?

 

[JohnW2]

Isn't he talking about a pull cord - which could be (re)wired to turn it off permanently?

If it's in the supply to the fan then, yes, it would certainly be able to 'turn it off permanently'. However, I thought he meant that he wanted it usually to come on with the light (with a timer over-run), but with the ability to stop it coming on with the light if he wanted (e.g. at night) - in which case all my previous comments apply.

If he doesn't want it to ever come on with the light, then he could obviously wire it so that the only control was a pull switch.

I guess we need him to clarify his requirement.

Kind Regards, John

 

[blup]

In the shower room in question, which has a fixed main window with a small opening top light, a great deal of steam and moisture builds up, and so the overrun was set at maximum - around 25 minutes. Mildew builds up if the fan is not used.​

Essentially the plan is that the fan would be switched off at night, and on in the morning, or whenever in the day or evening it was needed to extract steam from the shower. Having experienced a very noisy Aspira fan for about 14 years, with that kind of overrun, it was a mild relief when it finally failed.

I take John D's point - and will probably end up implementing his suggestion - but for the avoidance of doubt I would prefer to be able to isolate the fan at night, at the very least, to prevent any noise at all but also get maximum benefit from a timed overrun.

Cheers,

Blup

 

[JohnW2]

Essentially the plan is that the fan would be switched off at night, and on in the morning, or whenever in the day or evening it was needed to extract steam from the shower.

Fair enough, but that relies on a fair bit of memory, and I'm pretty sure I know what would happen if I had such an arrangement in my house

Kind Regards, John

 

[EFLImpudence]

I would prefer to be able to isolate the fan at night, at the very least, to prevent any noise at all but also get maximum benefit from a timed overrun.

You are using the word 'isolate' - which we use to mean make it electrically safe to work on, i.e. using a three-pole switch.
What you require, for what you want to do, is merely switching it off - for which a pull cord in the switched live will suffice.

 

[JBR]

Thanks, I'd missed that the Xpelair model with the pull chord didn't have an overrun timer which is what, ideally, I want. There is a version with a humidstat but other posts on this site suggest they're not efficient or effective.

I could install a three pole pull cord isolator switch within the shower room, but have assumed that this would be notifiable work as there is none at present.

Is there on the market a quiet, reasonably priced, replacement 4" wall mounted fan extractor, with built in pull cord and adjustable timer?

Cheers

Blup

Yes, the one I listed earlier, but with a pull cord included:

http://www.cef.co.uk/catalogue/prod...nt-selv-fan-c-w-adjustable-timer-and-pullcord

EDIT: My apologies. It seems that this model is 12V rather than 240V.

An alternative would be to wire in an isolation switch. I have such a switch right next to the fan, so it can be turned off if not required.

 

[ban-all-sheds]

In the shower room in question...

What sort of shower is it?

 

[blup]

Hi B-A-S,

It's an electric shower.

Cheers

Blup

 

[ban-all-sheds]

Do you mean electrically heated, i.e. not pumped?

 

[blup]

B-A-S,

It's electrically heated, not pumped, about 10.6kw on a 50A rcd protected mcb.

Cheers ,

Blup

 

[ban-all-sheds]

Does it have an isolator in the room which you are all accustomed to turning on and off every time you use the shower?

 

[blup]

Yes.

 

[ban-all-sheds]

Take the shower circuit through a contactor, coil on the lighting circuit, with the "isolator" switching the contactor and the fan on/off. You could replace the existing switch with a smaller 6A one if you wanted. If the room is big enough you could do away with all the dangly cords.


Alternatively, if you have plumbing skills and can access the shower supply pipe after any other branches you could put a flow switch in the pipe and use that to trigger the fan. Would involve more cable to conceal in the room though, compared to using ceiling switches.

 

[blup]

Food for thought...

OOI could a contactor be used to switch between two electric showers, thus saving on an additional fuse/rcd etc, and avoiding problems with overload at the CU?

And do you know of any makes that would be suitable?

Cheers,

Blup