New extractor fan overrun timer not working

zepman

So, we had our bathroom fully renovated in the past week. All good except the new extractor fan doesn't stay on once we turn off the light.

The fan is a Vortice ARIETT T (https://www.amazon.co.uk/gp/aw/d/B00G974ZK4?psc=1&ref=ppx_pop_mob_b_asin_title). It comes on when the bathroom light is turned on, and turns off with it. It also shuts off when the isolator switch is turned off. The only issue is that there is no overrun. The older fan we had (CATA CB-100) used to have the overrun working fine so there shouldn't be anything wrong with the setup and the only change is that the fan is new.

I've adjusted the timer dial to different positions but it doesn't make any difference. I'm wondering now if it's just a wiring problem. Below is the wiring diagram from the product manual and pictures of how it is currently wired.

On the supply side, there are two brown wires, so one of those should be a switched live and the other a permanent live. But which is which?

I'd prefer to get an electrician in to sort this out but would like to try and understand this myself first.

10-10-20

It's a very common issue. You can only really tell with a voltage tester or a multimeter.

But if you look at the incoming three wires, are they all individual singles, or is one a twin & earth in one? If you have a twin & earth, then look to see if you also have a twin & earth at the back of the wall switch, and that would indictate that the brown out of the T&E is the switched-live.

Otherwise, I'd do this: Isolate fully first, then swap both brown live connectors over. Then power back up and re-test.

zepman

Cheers! I had given the bathroom shop a call yesterday to send their lads over to have it sorted. But they were likely busy in another job.

About half an hour after I posted on here today, they showed up and fixed it. 😀

It was indeed just a matter of swapping over the brown live wires. This is something I could have done myself. But I don't have a voltage tester or a multimeter, so even after turning off the isolator switch and the MCB, I couldn't be certain that the wires are safe to touch.

kirk.

That schematic isn't correct .The isolator is switching off the fan and light

I don't know why they show 2-pole isolators upstream on schematics