John Rumm wrote on Oct 23, 2009:

Mike Lane wrote:
A very elementary question which most of you wouldn't have to think twice
about, but...

[snip]

I'd be immensely grateful for any (practical) advice - thanks.

In general it ought to be straight forward. However, there is a gotcha!
If the vent exits directly out of the back - it will probably be in the
middle - however that not guaranteed. I would suggest you take yours off
(looks like a bog standard Hygena / MFI unit), and measure the position
of the hole so that you can check the new one matches before you buy it.
(the current one is held on 2 screws and the top at the back - you get
to them by flipping the bottom panel down.


Aha - yes! It is indeed a Hygena (model APM2121). The unit doesn't have the
maker's name on it anywhere. That's a great help thanks.

This makes me think that my best bet would be to try and get an identical
replacement. Presumably then replacing it would be quite simple (maybe even
someone as clueless as myself could do it).

--
Mike Lane
UK North Yorkshire
mike_lane at mac dot com