On Wed, 26 Jun 2013 15:29:40 +0100, thescullster wrote:

Does a heat source like a radiator change atmospheric pressure?

Not that would be measurable by that instrument in a normal (non-air
tight) house. B-)

Can I mount this on a wall above a radiator and expect it to work?

I wouldn't, as others have said the oak won't like it and if you are
getting wide temperature variations (rad on v rad off) that could
affect the readings as the works expand/contract. Try an find a place
with a fairly stable temperature to be kind to the wood and the
instrument.

From my memory of the barometer, the needle doesn't appear to move much
in operation. Is this because it was previously in a centrally heated
house, or is there likely to be something wrong here?

Well ATM the UK is under the influence of a high pressure and it's
not changing very much at all.

Normal sort of range would be about 29.25" to 30" of mercury (1000 to
1030 mb) changing from one to the other normally over couple/three
days. Though it can change faster. These type of barometers might
need a gentle tap to make the needle move properly to the current
pressure reading. There also ought to be a small adjustment screw to
compensate for your locations altitude, so the instrument reads "sea
level" pressure. Now is not a bad time to check that as most of the
country is pretty much at 1032 mb (30.5" Hg)

Depending on how windy it is and how exposed/draughty your house is
that can cause a few mb of reduced pressure inside by venturi effects
of chimneys etc. I've noticed on several occasions when a gale
suddenly stops there is a coresponding step up in the air pressure.

--
Cheers
Dave.