Thanks very much for all the replies on this. You gave me the pointer
that I needed (and it _was_ the white wire, incidentally) - thermostat
now installed.

Appreciate the help.

Cheers
Jimmy


"BigWallop" wrote in message ...
"Peter" wrote in message
...
This will normally be the white wire on a mid position valve, ie CH call

Some valve heads vary in their wiring scheme, so I can't really say which
colour wire would be where.


"BigWallop" wrote in message
...

"Jimmy" wrote in message
om...
Does anyone have a wiring diagram for one of these wiring centres that
they could email? I've got one of these installed in a fully pumped
domestic central heating system with a single mid-position zone valve;
there's no room thermostat, and I would like to know where on the
wiring centre I should insert one.

Thanks
Jimmy.

Find out where the zone valves are connected in the box and break in to
the
one which controls the heating circuit. What you're looking to do is
make
the room 'stat switch off the zone valve on the heating circuit and stop
the
water flow around only that part of the system. Make sure the room
'stat
is
only controlling the heating side of the system so that it doesn't
switch
anything else off when it reaches the temperature you've set.