Fan Confusion

chuckalicious · 9 Mar 2017

Ok. Had an extractor fan replaced. The old fan turned on when the light went on and then kept running for a set amount of time after the light was turned off.

However I had originally specced a humidistat and timer controlled one which was fitted today while I was out.

However, now that the new fan is in, it only turns on once the light is on and the humidity hits a certain level, which is fair enough, however, when the light it turned off it goes off immediately, which shouldn't happen.

I have taken a look as I think I understand how it should work - a live, neutral and a switched live cable. Indeed there are 3 cables. However, the live is only live when the light is on and what is connected to the switched live is only live when the light is off.... I can't understand how the last one worked.

If I swap the 2 "live" cables over the fan comes on if the humidity is right and the light is off and turns off when the light is on.

Any ideas? It took so long to get the guy to come back that if it is something simple I'd rather sort myself.

Cheers.

ColJack · 9 Mar 2017

It's the switch end..
take the one which is suppose to be permanently live and connect it to the one in the switch that is permanently live.. ( after checking angturning off the power of course.. )

ColJack · 9 Mar 2017

To clarify.. the switched live at the fan should be the one that's on when the light is on, the other one is the one mentioned above..

chuckalicious · 9 Mar 2017

Thanks. Will check the switch end tomorrow when the light is better

Still can't see why the other one worked. Essentially what I'd like is for it to kick in when the humidity reaches the set level regardless of whether or not the light was turned on.

chuckalicious · 9 Mar 2017

Just had another look and I forgot the fan has an isolator switch higher up (which is always on). That has clearly been opened up today as the paint has been distributed but the light switch hadn't.

I have attached photos which will hopefully make more sense to you than me!

EFLImpudence · 9 Mar 2017

Grey is Neutral and connected to L at the fan.

Swap Grey and Black.

If, then, it still doesn't work properly, swap Black and Brown at the fan - leaving Grey in Neutral.

333rocky333 · 9 Mar 2017

Well providing the switch was correct the grey Neutral looks connected to the L terminal in the fan which is wrong

chuckalicious · 9 Mar 2017

Ta. Will give it a shot once the kids are in bed.

333rocky333 · 9 Mar 2017

Who put this fan in, you say he looked in the switch, so surely he would have seen the grey connected to N, its quite possible that the N is not being used for the neutral, do you have something to test voltage and feel competent to do so, rather than moving wires willy nilly.

chuckalicious · 9 Mar 2017

333rocky333 said:
Who put this fan in, you say he looked in the switch, so surely he would have seen the grey connected to N, its quite possible that the N is not being used for the neutral, do you have something to test voltage and feel competent to do so, rather than moving wires willy nilly.

I have a multimeter yes. If I feel out of my depth I will try and get the guy back.

mikeyd · 9 Mar 2017

chuckalicious said:
Thanks. Will check the switch end tomorrow when the light is better

Still can't see why the other one worked. Essentially what I'd like is for it to kick in when the humidity reaches the set level regardless of whether or not the light was turned on.

Yes, I too find it's always better to work on a lighting circuit in daylight hours. Don't touch it tonight.

I don't think you need to alter anything at the switch end.

I'm sure you see now why the old one worked, given the replies since the post I'm quoting.

As suggested below (or above this) whoever swapped the fan really shouldn't have left it like that. I'm not into 'naming and shaming', but if you could at least get a message to them or their supervisor, hopefully they can act on feedback.

Please let us know how it goes.

chuckalicious · 9 Mar 2017

With regards to who did it, I'm not 100% sure. The fan is in an extension we had done last year, which has been the subject of a few threads on here.

Long story short, outstanding issues on the build were getting ignored/fobbed off and so I had to send a letter stating the contractor had 14 days to sort all issues or I would keep the retainer. Funnily enough someone was out pretty quick to sort most of the issues. A guy was working in there today and I was out most of the day. Came back and he had gone for the day and I then noticed a new fan.

Could have been the original electrician or it may have been the same guy doing everything else.

It was so much effort to get it sorted in the first place I just envisage excuses of "that's what you asked for", "it can't work like that" as that seemed to be the type of guy he was.

Very frustrating.

chuckalicious · 9 Mar 2017

Just had another quick look and youre right, the grey neutral which followed through both switches was not in the neutral of the fan.

Swapped it and one of the lives and it still turned off with the light. Swapped the lives round and it is now working as it should be.

Thank you everyone.

mikeyd · 9 Mar 2017

Thanks for the explanation. Sound's like you're just wanting it sorted. I understand that very well.

Leave it until you are sure you know which wires to swap. It's obvious, but if you aren't sure, ask again (daylight hours)

Photos are good, and keep a copy or link to this thread in case the situation goes downhill.

Obviously I know nothing about the issues your contractor has with you, or vice-versa. I sincerely hope it works out though.

Edit: I'm way too slow. Was cooking a pizza.

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Fan Confusion

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