Hi Christian,

In . net,
Christian McArdle wrote:
It's getting louder. I've followed the pipes all around the house;
it's worst in the concealed part between the landing floor and the
kitchen ceiling.

Pull the main power isolator on your consumer unit. Does the noise
stop? If so, you've got some malfunctioning electrical equipment or
wiring somewhere.

It's definitely hydraulic, not electrical. Somewhat better today in that
it's intermittent, but I've no idea why it happened. For once, it wasn't
anything I did.

Cheers,

--
Gill
calmer after a few hours sleep