EricP wrote:

On 8 Oct 2006 06:01:49 -0700, "Adam-the-Kiwi"
wrote:

EricP wrote:
On 8 Oct 2006 02:31:42 -0700, "Adam-the-Kiwi"
wrote:

-8- snip -8-

If so, you have TRVs and they are on the wrong side of the rads.The
closing valve is vibrating as the water flows over it.

Have you had a new pump installed or turned up the flow?

No and no. The system was working fine last winter, and we've only just
turned it on for this winter.

Ok, go to the lockshield valve on the other end of the rad and close
it completely and then open it half a turn or until the rad works
again. Keep opening it a half turn until the noise returns and then
close it until the noise stops or reduces.

Apologies for the delay in responding...

That did it - thanks.

Cheers - Adam...