Bathroom Extractor Fan Problem...

[Billy Whizz]

I should have put Bedfordshire really. I'm not actually in Luton but it is the closest big town to my village. Convenient mid-point between work and family.

 

[Billy Whizz]

No Lee42, when in the switched configuration the fan stops as soon as the light switch is turned off, regardless of timer position.

 

[Lee42]

No Lee42, when in the switched configuration the fan stops as soon as the light switch is turned off, regardless of timer position.

But in the other configuration u said the fan ran constantly. Could that of been because the timer was set to max making it seem the fan ran constantly.
Just a thought.
I have been given faulty fans before, but to get two in a row is very unlucky

 

[Billy Whizz]

Correct Lee42, originally it ran as soon as the CU was turned on. But with the light switch off it should never have started, surely? Any timer should only kick in when an "on" light is turned off?

Bloody confusing...

 

[Billy Whizz]

I wonder if it runs on initial application of line power to set the timer? Let it run to cut out then maybe the switched control will work? Might try that while I'm on the inevitable phone "hold" tomorrow...

 

[Lee42]

Correct Lee42, originally it ran as soon as the CU was turned on. But with the light switch off it should never have started, surely? Any timer should only kick in when an "on" light is turned off?

Bloody confusing...

Im out then
Yes you are correct you need to switch the light on to activate the fan.
Without physically looking at it not sure what else to suggest.
Good luck with finding the problem

 

[Billy Whizz]

Im out then
Yes you are correct you need to switch the light on to activate the fan.
Without physically looking at it not sure what else to suggest.
Good luck with finding the problem

Thanks Lee42, much appreciated.

Best regards,

BW

 

[Billy Whizz]

Right!! A fresh and rested pair of eyes (and ears) sorted it this morning!

I turned on the CU and let the fan run to see if it stopped, which it did after 30mins. Timer adjusted, light switch on, lights on, fan on. Waited 30secs, light switch off, lights off, fan ran-on for 10mins! Perfick!!

The fact it originally ran uncommanded threw me as, from a DIY'ers basic safety perspective, there appeared to be an uncontrolled live. In hindsight, it was the de-energised timer relay (no SL) waiting for a Live to start the timer, which was provided by switching the CU.

The supplied instructions really need to have that explained. Just a simple "Fan will run initially to reset the timer" would do.

Thanks for your help everyone, i'm off to sort the CPC, single insulation, identification...

 

[westward10]

Well done Billy.

 

[GlenTavener]

Obviously not a professional job. However, trying to cross check your diagram with the junction box it would seem that you have crossed connections at fan in that the switched live which seems to be the grey wire is going to neutral and the black wire is going to the switched live position. The probability of two fans being faulty though not impossible is remote, its almost certainly your wiring.