On 02/01/2014 10:23, Brian Gaff wrote:
I'm 90 percent certain its the neighbours Central heating. I suddenly
remembered the old tumbler against the wall trick, and the loudest noise
is now located to the partywall between my airing cupboard and hers. (I'm
glad I left enough room here for my head!), and its definitely kind of
cyclic noise. I think it is actually going for longer than i said, its as if
its only when its nearly ready to cut out that it makes the noise.
Weird, as I'd have expected it to be off for longer, but who knows.
Brian

HI Brian

Could it be a motorised 'zone' valve - that's diverting hot water from
their boiler to radiators or hot-water cylinder.

I have one on our heat-pump in the workshop - and it takes a while
(possibly 60 seconds ? - I've never timed it) to switch from one
position to the other - and it's very much a 'clockwork whirr' while
it's operating. I think that some of these valves return to a 'rest'
position when you take the power off..? That might be what you are
hearing....?

Possibly the motor is wedged against something (wall / woodwork etc) and
this is acting as a sounding-board. Bit of carpet offcut between
whatever's touching might solve it ?

Adrian