In message . com, Jules
writes
On Tue, 01 Dec 2009 09:28:26 +0000, Tim Lamb wrote:
I have tried releasing water to see if grit has lodged in the seating
without success.

Hmm, wonder if you can strip it and reassemble and still expect it to work
(i.e. whether the pressure at which it trips is inherent in the design,
or if it's dictated by how tightly some part or other is torqued upon
assembly)

Possibly. Unfortunately, if I wreck it attempting a repair, my tenant
will be without a supply for hand washing.

I suspect there's still a particle of something or other stuck in there,
but disassembly might be the only way to get at it.

Yes. Peter has given me a source so the plan is to wait for the
replacement to arrive before attempting anything.

These heaters seem to originate from Italy although Santon et al have
their own versions but fitted with different over pressure arrangements.

regards

--
Tim Lamb