What kind of switch for inline extractor fan?

[donnywong]

Dear all,

I am having an inline fan installed to assist with clearing the air in an internal windowless bathroom that is experiencing condensation problems.

The bathroom has an existing ceiling mounted exhaust fan that just does not do a good enough job (in part because the developer of my flat installed the exhaust for the fan to vent out to the back of the house using a very long 8-10meter 100mm exhaust pipe). The existing fan is connected to the light switch and comes on any time the light switch is turned on.

I would like the second fan to come on only when I am taking a shower. I have opted NOT to buy a fan with a humidistat after hearing too many stories about them coming on by themselves at odd times (like when it is raining outside, or if you are cooking in the kitchen and some steam gets in the air). The Vent-Axia inline fan I purchased does have a timer attached.

So my question for you guys is, is there a type of switch you can recommend that functions like an "on button" rather than as an on-off switch for the fan? That way, I can let the fan's timer take care of turning the fan off whenever I take a shower. I don't want to use a pull cord if I can help it as they are not very attractive. And I don't want to connect the fan to the light switch since the existing exhaust fan is already connected to the light, and because the inline fan will be mounted in my bedroom, and I don't want it turning on in the middle of the night when I use the toilet.

any suggestions would be great appreciated!

[Owain]

Your timer fan will have connections for live / trigger / neutral (and earth). It must be connected via a 3-pole fan isolator switch eg

reach of the fan or a lockable one if remote from the fan eg live / neutral to the permanent supply and put a momentary (retractive) switch between live and trigger. This will start the fan running for the period set by the timer. Eg

[chris French]

In message , donnywong writes

Actually, I had a humidistat controlling the fan in our old bathroom, and it worked pretty well. Very occasionally, when it had rained heavily and for long enough it would nuisance trip, but mostly not. Kitchen steam wasn't an issue (though I suppose it might be if it was very near bathroom)

But for your case, flow operated switch on the shower feed switching the trigger live would be a neat way of doing it.

[The Natural Philosopher]

I have a humidistat fan that also comes on when the lights are on as well.

Occasionally it does come on in very heavy rain But that's all.

Frankly I like it that way, there's a bog in there as well as a shower and bath and it helps clear the air.

Far more irritating is the smoke alarm just outside the bathroom which is guaranteed to utter ear piercing screeches and set off all the interlinked alarms when my wife takes a shower and doesn't bother to close the door properly.

[Brian Gaff]

Well there are actually timer switches of course but that would negate the whole point of having a switch in the first place.

Brian

[Dave Liquorice]

I like that idea. But as some one else pointed out is there anywhere for air to get into this internal room? 8-10m of 100mm is rather a lot but if there is no provision for decent air entry it's going to be even worse.

Does the OP close the door after a shower or leave it a little open to allow air in? Leaving the door open is much cheaper and simpler solution that installing another extractor that won't work if there is no where for air to get in...

[David WE Roberts]

Discussing this with our electrician at the moment.

The solution he uses at home is a fan with a delay timer, and an external (to the bathroom) switch. So when he wants the fan on he just switches it on outside the bathroom door, and then it runs on after the switch has been turned off. Simple control, if you don't want a pull switch. Also works with a humidistat fan AFAICS.

I want what I had in the previous house, i.e. Run on timer for the fan. Humidistat. Override switch Not coupled to the light.

This allows the fan to clear steam from the room, and only stop when it is clear. This allows you to turn on the fan when you are taking a dump (even in the dark) and have it turn off automatically. This allows you to go and have a wee and/or brush your teeth last thing at night without the fan coming on.

Last time an Xpelair humidistat was used which also had an override switch (pull cord). We had two fans, one over the toilet and one over the shower, both controlled by the same controller. It worked really well, although there was only a short duct run in the loft.

Cheers

Dave R

[Scion]

Owain spake thus:

it? Seeing as some (all?) fans require a fused line a switched fused spur would make more sense,

for example even has a lockable captive fuse holder for locking off.

[David WE Roberts]

I think this may be because you have two seperate power sources - the permanent mains power and the temporary trigger power. So all incoming wires to the fan should be isolated before working on the fan.

[Scion]

David WE Roberts spake thus:

D'oh! Of course. I left my thinking brain at home today.