150mm timed extractor fan not working with timer function (photos of wiring)

Vedb · Nov 26, 2024

Hello all!

I've got a peculiar issue whereby the wiring of an extractor fan seems to be wrong (but working) however it doesn't allow for the timer function to work off the permanent live. Please take a look at the photos to show you the inputs, the wires and also the only configuration which allows the fan to come on with the switch. I'm confused as to why the inputs don't match in the conventional way and also why the permanent live won't keep the fan on after switching off the light. Any advice?

Much appreciated!

Vedb · Nov 26, 2024

binky · Nov 26, 2024

Try swopping the black and brown, some peopleuse brown as permanent live, some people don't .

How do yuo know what is permanent live an switched live?

ProDave · Nov 26, 2024

How do you know which is N?

SPECIAL LOCATION · Nov 26, 2024

Have you actually tested the conductors to confirm which colours have been used for each function?

Or are you just guessing?

Vedb · Nov 26, 2024

That's just it, the usual colouration doesn't apply here and I don't know why it was wired this way. However the only combination which works is the one I've shown on the photo, otherwise the fan doesn't power on.

You can see what they're labeled as on the fan so the assumption is that the wires then correspond to these with black being live, brown timer and grey neutral. I've tried them every which way to see if I can get it right but it always comes back to this.

Vedb · Nov 26, 2024

An update,

It also works in this configuration. Which I've copied from the fan in the bathroom. However it also does not stay on when the light is switched off.

Andy™ · Nov 26, 2024

you need to do some actual testing of the cables coming in to see which cable does what. winging it and randomly trying different combinations will either not work, or do damage and not work

Vedb · Nov 26, 2024

Thank you. There's only so many combinations it can be so I wanted to do this without having to call someone in, who also may not be able to do it.

I've not had to test wires before, can someone recommend good gear for testing?

Andy™ · Nov 26, 2024

simple voltage tester will do

there is only so many combinations, however get them wrong, and chances are you've damaged the PCB so matter if you do then get the right combination afterwards, the damage is already done

ProDave · Nov 26, 2024

Unfortunately there is no defined standard of which colours to use.

If there is a fan isolator switch have a look inside that, they are often labelled and that might give you a clue.

Richard-the-Ninth · Nov 26, 2024

Why are you "adjusting" it. What happened prior to you touching it, did it not stop or the over run not work, or something else?

SPECIAL LOCATION · Nov 26, 2024

Vedb said:
who also may not be able to do it.

Very unlikely they would not be able to do it!

An electrician with proper test would have identified the wires and confirmed if the fan timer itself is faulty or not probably quicker than it took you to post the question & photos.. 10mins work.

If it used to work, (from the photos it doesn't look like its a new fan?), and has now stopped working.. Then most likely its the timer circuit board that has failed....
As there would be no logical reason to assume the wiring was wrong..

I'm not sure how robust that timer PCB is..?
But as Andy said it is never a good idea to just randomly swap 230v wiring connections around when trying to get something working..

SPECIAL LOCATION · Nov 26, 2024

Vedb said:
I've not had to test wires before, can someone recommend good gear for testing?

A basic AC & DC voltage polarity tester can be purchased from Screwfix for just under £60
https://www.screwfix.com/p/kewtech-kt1780-ac-dc-2-pole-voltage-tester-690v/53370

BUT I would NEVER recommend anyone who is not familiar with electrical testing to do any live testing..

Plus that is more than I would charge you for half an hours work max, to come and test and fix your problem!

150mm timed extractor fan not working with timer function (photos of wiring)

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150mm timed extractor fan not working with timer function (photos of wiring)

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