EXTRACTOR FAN WITH TIMER ON/OFF/ON/OFF?!!!!

My apartment had a Vent Axia inline extractor fan installed when it was built in 1999, this stopped working about 3 months ago.

The original plans show the fan was a model ACM100. I knew it had a timer as this was operating at the time it was working. When i went upto have a look, i couldn't find the model no. just soem tech info but it was a Vent axia and it was 100mm ducting. I ordered a new ACM100T fan from GIL-LEC (great online retailer as i'm sure you know).

I removed the old fan and replaced with new using the old housing/connection for the ducting but with the new fan unit. Connected all the wires up as before (minus the earth as they are now double insulated).

When i turned the power back on the fan is working the OPPOSITE way round way ie. when the light is OFF the fan comes ON and when the light is ON the fan turns OFF after the timer has lapsed?!!!!

I've spoken to Vent Axia and Gil-lec countless times now. They suggested the following:

1) live and neutral were the wrong way round - CHECKED both ways
2) Switched live and live are wrong way round - CHECKED both ways
3) The old fan may have been modified - CHECKED no evidence of it

They now say something is wrong with the wiring? How if it was working before?

Surely something simple is behind all this?!!

Please help!

What you need to do is check with a meter whether you are getting voltage between live and neutral. And between switched live (SL) and neutral ONLY when the light is on. If you get 240v between SL and N when the light is on, then there is a fault with the fan.

If you are not getting SL - N voltage, then you have a wiring fault. Possibly the lightswitch is 2-way, and the fan supply is wired into L2 instead of L1.

Sounds like switched live & neutral are the wrong way round to me, but as sparkyspike says the only way to do it properly is with a meter.

Thanks for the quick reply. I have a meter so i'll give it a try