Hi,

The "diverter valve" has gone bang on my mum's central heating system
and we are told that it is obsolete.

The system looks very much like a modern Y plan system - fully pumped, 3
port valve, separate timed control of heating and hot water, etc. The
only difference from a modern Y plan system is that the wiring box
contains a relay.

The plumber is being useless, so I may have to do the work myself, it
should be a straightforward task to replace the "diverter valve" with a
modern 3 position valve and replace the wiring centre with a modern one
without the relay.

The tedious bit will be identifying all the unlabelled wires coming into
the wiring centre - a task which would be made a lot simpler if I had a
wiring diagram.

Does anyone recognise the description of the system and have a wiring
diagram they could scan for me (or point me to one on the Internet). The
system is of mid 70's vintage (1976 or 1977 I think) and the diverter
valve and wiring centre are made by Satchwell. Unfortunately I am unable
to see any part number on the diverter valve.

TIA,
Martin.