Extractor fan timer is random

[portuguesejohn]

Recently moved house and noticed the extractor fan in one of the toilets was struggling - the fan was very slow. One time I switched off the isolator and the fan never came back up once I turned it back on.

Just now got around to fixing it by replacing it with a very close model (if not the same exact model), a "Manrose XF100T". This thing has a timer, but not a humidity sensor or anything like that. I left the timer at the factory value of 1 minute, which is good enough for my use.

Wired it up, turned it on, works great. Turned off after 1m - Great! Today is a different story... The fan, to put it simply, seems to run on a random timer for the switch off, behaviour is as follows:

- Light switch on: fan kicks in.
- Light switch off: fan runs for... 1m, 3m, 15m... it seems completely random every time we use it!
- I have also noticed a very strange behaviour while doing some tests: Light off, isolator off, then turn on isolator switch (light still off!) - fan kicked in! How?? I have been able to see this once, though.

Please find attached the wiring and instructions, I am definitely no electrician, but I thought this one would be easy enough!

 

[portuguesejohn]

Just now went past 30m, fan still going while light is off... Which is over the stated time limit in the instructions!

And I have managed to trigger more of that strange behaviour where both the light and isolator are off, then turning on the isolator and that starts the fan - again, does not happen all the time, but I can also see the light flicker very briefly when I switch the isolator switch back on!

 

[Wayners]

Faulty timer then.

You can bypass the timer so it work's with light or return for one that works

 

[portuguesejohn]

Faulty timer then.

You can bypass the timer so it work's with light or return for one that works

I am starting to think there is something about the wiring here that is not right... I can now fairly often see the odd behaviour of having both light and isolator switches off, THEN turning on the isolator on (only the isolator!) and the fan starts going! I also see my light flicker briefly as I switch the isolator switch back on....

 

[endecotp]

You appear to be using the earth conductor as the switched live.

Don’t do that.

 

[portuguesejohn]

You appear to be using the earth conductor as the switched live.

Don’t do that.

The old fan, which was the same model, had the exact same setup (explains why it stopped working?) - what can I do here?

 

[pete01]

Disconnect the earth wire (it shouldn't be used as a live wire)

Join live and switched live together and have the fan come on and off with the light.

 

[endecotp]

what can I do here?

You should use 3-core-and-earth wire.

Of course this doesn’t, by itself, explain the problem you are seeing. But it does indicate that the original fan was installed by a bodger, and there could be other bodges that you have not discovered yet.

Personally, I would remove the fan and connect it to a plug and see if you get the same problems. If you do, the fan is faulty and you should return it. If it works correctly in that case, there must be an issue with your wiring. Doing this (safely) does require a bit of electrical skill though…

 

[portuguesejohn]

Am I right in thinking this wiring was not supposed to be used for a timed fan, maybe it was originally setup for a non timed fan (just L and N) but someone that does not know anything (such as myself!) decided to get a timed fan and just thought "well this earth needs to go somewhere!"... Would I be OK just returning this fan and get a basic one without a timer? (I don't need the timer feature at all), would I just not connect the earth at all and just sleeve + tuck it?

 

[SUNRAY]

Using the earth wire as a live is very much frowned upon but adding a brown sleeve or tape

would make it compliant.


The copper wire looks a little untidy with exposed copper and is that a 'whisker' sticking out just above the blue, it could do with a chackup and tidy.



However if you don't wish to have the timer operational then do this link wire and make the earth wire safe
INCLUDING MOVING IT IN THE ISOLATOR FROM THE SL TERMINAL TO THE EARTH TERMINAL

Also double check that the fans terminal markings are as I have marked as not all follow the same sequence.

 

[opps]

Using the earth wire as a live is very much frowned upon but adding a brown sleeve or tape View attachment 394142would make it compliant.


The copper wire looks a little untidy with exposed copper and is that a 'whisker' sticking out just above the blue, it could do with a chackup and tidy.



However if you don't wish to have the timer operational then do this link wire and make the earth wire safe
INCLUDING MOVING IT IN THE ISOLATOR FROM THE SL TERMINAL TO THE EARTH TERMINAL

Also double check that the fans terminal markings are as I have marked as not all follow the same sequence.
View attachment 394146

Am I wrong in thinking that the cable running to the appliance must have an earth even if it is not connected to the appliance? By that, I mean I thought that it offers extra protection in the event of someone cutting through the cable further "upstream" ?

Please feel to correct me. I learn a lot from you guys.

 

[endecotp]

if you don't wish to have the timer operational then do this link wire and make the earth wire safe

That will cause it to run continuously; he needs to also change the wiring at the other end of this bodged wire.

Also double check that the fans terminal markings are as I have marked as not all follow the same sequence.

He posted a diagram earlier and it does seem to be correct, i.e. N SL PL from top to bottom.

 

[EFLImpudence]

Am I wrong in thinking that the cable running to the appliance must have an earth even if it is not connected to the appliance?

No you are not wrong. That is correct. The reason is to cover future need for it.

It has only just been altered to prohibit over-sleeving a green and yellow cable for other use even if there were an additional earth wire present.

By that, I mean I thought that it offers extra protection in the event of someone cutting through the cable further "upstream" ?

No, not really; cutting L & N has the same effect.

 

[opps]

No you are not wrong. That is correct. The reason is to cover future need for it.

It has only just been altered to prohibit over-sleeving a green and yellow cable for other use even if there were an additional earth wire present.


No, not really; cutting L & N has the same effect.

Thanks (yet again). I was thinking more of live to earth bridging in the cable if someone were to partially cut through it.

 

[EFLImpudence]

Thanks (yet again). I was thinking more of live to earth bridging in the cable if someone were to partially cut through it.

What about live to neutral bridging in the cable if someone were to partially cut through it.

I don't see the difference.