"Ed Sirett" wrote in message n.co.uk...

Most like the zone valves are the type which go around a full circle.
IIRC these valves need a connection to make them shut off as wellas a
connection to make then open. Hence the relay, although they could have
made use of the changeover contacts in the stats.

3 double pattresses seems excessive.
I'd reckon getting all the wiring for S-plan in one double patress with
a 12-way choc-strip. ( Earth and Neutral 2 terminals each as there are
more than 4 wires of each on those).

Sounds like you may have hit the nail on the head, like I said the
zone valves appear to be ancient, or at least a plumber mate said so:
"Haven't seen those in years" etc. They do appear to be making use of
the changeover contacts in the stats and programmer as well. The relay
does seem to be associated with the white wire from the zone valves -
the orange wires pretty much go straight to the boiler & pump.

BTW Ed, you might have got the wiring into one double patress but you
need a second one to house the relay ;o)

Andy