HELP - Delayed ON Timer 240V

ecoleman

ecoleman

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I'm looking for some help from any electicians / electronics buffs please.

I've just installed an extractor fan in the loft for our bathroom as we get quite a lot of condensation on the walls and windows during baths / showers especially in the winter.

The extractor is wired with a permanent live and a switched live and I currently have it set to run for approx 20 minutes after the lights are turned off. All good so far.

However this also means the fan runs for 20 minutes even if you just pop in to use the loo. So, I was hoping to fit some sort of timer inline on the switched live so when the bathroom light is turned on it activates the timer, if the switch is still on after say 2 minutes will energise the load (extractor fan). Obviously if the light switch is turned off before the timer kicks in then the extractor never runs.

I've found various DIN rail mount stuff and relays that can be fitted ti circuit boards but was hoping to get something simple to install. something that can just be wired inline with the switched live and neutral.
 
We have an extractor fan, and this does get rid of most of the steam. But I still find it's better to air the bathroom off, by opening a window after a shower. This seems to do the trick, otherwise mould can start to form.
 
Firstly, please tell me that your extraction goes through the loft into the outside world, extracting warm/moist air into a potentially cold loftspace is a recipe for condensation which potentially causes mould/rot within the loft

Various solutions to your problem could include a second light circuit, or in our case a mirror with a touch light. You could also look at a simple inline switch or pull cord to enable/disable the extraction unit, it will still continue running even after the pull cord is switched off (from the permanent live)
 
Lets assume that the extractor is correctly installed shall we.

I could install a pull cord but that would also involve getting certain people in the house to remember to turn it on before having a shower. I would rather not have something that has to be turned on or off manually
 
If your fan electrics are in the loft, just fit a DIN rail mount delay timer inline using the switched live/neutral then. Plenty of 2 module boxes available from the likes of screwfix, with and without covers. Fit one module and one blanking plate.

(Obviously a waterproof enclosure might be beneficial depending on the extraction installation ;) )
 
Mr Perceptive said:
If your fan electrics are in the loft, just fit a DIN rail mount delay timer inline using the switched live/neutral then. Plenty of 2 module boxes available from the likes of screwfix, with and without covers. Fit one module and one blanking plate.

(Obviously a waterproof enclosure might be beneficial depending on the extraction installation ;) )
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That is an option although the din rail stuff is quite expensive. I was hoping for a cheaper simpler alternative but will certainly go down this route if need be.
 
We have a timed fan in the bathroom and if we just need to nip in for a short while and don't need the fan to stay on, we just switch the main power to the light and fan off momentarily using the shorter stringed pull switch. If it's left switched off, the light doesn't come on when the longer cord is pulled so there's no chance of the fan being left off while someone's showering. Not sure how it's all wired - it's under insulation under boards in the loft!
 
I set the fan in our en-suite to run for a couple of minutes after the light is turned off and then trained other members of the family to simply leave it on if they had a shower. I take the point about other family members but it didn't take to long for them to remember to leave it on.
 
sirch said:
I set the fan in our en-suite to run for a couple of minutes after the light is turned off and then trained other members of the family to simply leave it on if they had a shower. I take the point about other family members but it didn't take to long for them to remember to leave it on.
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I spend my life telling people to turn lights off behind them, now you want me to tell them to leave them on :eek:
 
IIRC, our bathroom light is a 6W LED fitting so has an almost negligible power drain compared to an incandescent lamp (or the fan!)
 
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