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And now for something completely different
jlparsons - 2/2/09 at 09:46 PM

Ok. Novel one this...

We've got an extractor fan in our bathroom, and it's a nice modern quiet one with a humidistat, but it still winds me right up when it comes on at night and runs for a couple of minutes after whoever finishes up and goes to bed. Solution?

A single 240v flow switch on the hot water in-pipe to the bathroom to trigger it when someone runs the bath/shower/sink instead of the light switch. After all it only needs to come on when someone runs the hot... unless they've just dropped the kids at the pool, in which case you'd hope they'd wash their hands anyway so problem solved. Yes I know you can just use the isolator but that means it gets left off permanently.

So... anyone know where I can find a flow switch? I figured that this sort of thing would be fairly commonplace as a central heating component, but a web search revealed nothing. Anyone know of such a thing?


jonesier1 - 2/2/09 at 09:49 PM

take the cover off the fan if its like mine there is a few really small switches in a block that you can set/adjust for time periods and off.worth a look.


Hellfire - 2/2/09 at 09:50 PM

Third one down. Any good?

Phil


Howlor - 2/2/09 at 09:51 PM

How come it runs for the couple of minutes? Ours purely cuts in when you have been in the shower for 5 minutes etc. Never heard it other than when showering. Have you got the humidistat set a bit too low?

Steve


jlparsons - 2/2/09 at 10:07 PM

quote:
Originally posted by Howlor
How come it runs for the couple of minutes? Ours purely cuts in when you have been in the shower for 5 minutes etc. Never heard it other than when showering. Have you got the humidistat set a bit too low?

Steve


Interesting, maybe I've set it up wrong. Is yours triggered purely by the humidistat then, not the light-switch? Or is one or the other, or both?


jlparsons - 2/2/09 at 10:08 PM

quote:
Originally posted by Hellfire
Third one down. Any good?

Phil


That's the badger! Not sure if I'll need it though, looking at Steve's post.


Howlor - 2/2/09 at 10:23 PM

Mine is purely triggered with the humidistat, although I have it so that you need the light on for it to work.

As I say it only comes on after about 5 mins in the shower.

If you want I could pop the top off and see how it's wired.

Steve


Howlor - 2/2/09 at 10:23 PM

Mine is purely triggered with the humidistat, although I have it so that you need the light on for it to work.

As I say it only comes on after about 5 mins in the shower.

If you want I could pop the top off and see how it's wired.

Steve


jlparsons - 2/2/09 at 10:32 PM

Ok, found a 250V 1A/15Watt flowswitch, £6. I like this cos it's like the budgee, cheap cheap!

Problem - the fan's going to draw more than that. Wonder if I could chuck a resistor in series to ensure it doesn't pull more than 1A across the switch at full power - would it still switch? Ho hum... thoughts?


jlparsons - 2/2/09 at 10:38 PM

quote:
Originally posted by Howlor
Mine is purely triggered with the humidistat, although I have it so that you need the light on for it to work.

As I say it only comes on after about 5 mins in the shower.

If you want I could pop the top off and see how it's wired.

Steve


Thanks for your help mate, no need to worry checking though - I found the instructions for mine and it says it does have to be triggered by the light, the humidistat purely keeps it on for longer if necessary. It was a B&Q one so it's probably not the bee's knees!


mad4x4 - 3/2/09 at 07:30 AM

Why not wire the trigger to the Shower switch instead of the light switch, So when some one switches on the shower isolator then the fan will come on and run. Then when the isolator is switched off (after the shower) it runs on for a time.


jlparsons - 3/2/09 at 11:02 AM

That'd be the best way to do it, without a doubt - but my shower is run off my combi boiler, there's no elastictrickery in it anywhere. Doh!


MikeRJ - 3/2/09 at 12:50 PM

quote:
Originally posted by jlparsons
Ok, found a 250V 1A/15Watt flowswitch, £6. I like this cos it's like the budgee, cheap cheap!



Where does the 15W rating come from? Contacts are not usually rated in terms of power.