The fan is switched on by the operation of the light switch. Normally it powers up to full speed imediately it is switched on. But now it revolves slowly for some minutes before picking up speed and running normally.

Jasper, December 2008

I had exactly the same problem. The bearings packed up - eventually it will stop working.

You can still buy this model. The fan assembly is mounted on a bracket held to the backplate by 3 screws. Loosen the screws, unhook the bracket and unplug the connector. Hook the new fan onto your original backplate (discard the new backplate that comes as part of the new fan asembly.

fidler, December 2010

The reason is the bearings are drying out. (pre-packed grease) these are not able to be re-greased, but a temporary fix is to spray with a light oil, both ends of the motor shaft and leave for an hour or so before re-installing the fan. gradually the bearings will absorb the lubricant.
evenyually you will need to replace the motor assembly.

Multi-Mike, March 2009

Take the fan out of the circuit and clean throughly checking all the connection are tight inside this sounds like a maintenance factor 'where all the sh*t builds up'

Max, February 2009