On Mon, 13 Nov 2006 10:18:38 -0800, FGoogle wrote:


So it appears that you can just use the one valve for your S-Plan system.
You just connect one switch wire to permanent live and the other to your
boiler call for heat, in parallel with your heating valve.

Christian.

OK

So back to the original question

The wiring diagram for S Plan shows permanent live (on grey) and
switched live from the timer (on Brown)

My Question was is there any reason I can't join the Grey wire to the
Brown?

Anyone?

Thanks

Mark


There is a good reason:

Firstly the Zone valves are often used in pairs (one for HW & one or more
for heating). If you connect the grey to the brown you will cause the
zone valve to latch in the on state until _all_ zones are satisfied.

It does not matter if the HW cylinder is nowhere near the heating zone
valve if the orange wire is live (because some zone valve somewhere is
open) then this zone valve will stay open because the brown wire (which
opens the valve) is connected to grey and (via the switch in the valve) to
the orange and so the live.

--
Ed Sirett - Property maintainer and registered gas fitter.
The FAQ for uk.diy is at http://www.diyfaq.org.uk
Gas fitting FAQ http://www.makewrite.demon.co.uk/GasFitting.html
Sealed CH FAQ http://www.makewrite.demon.co.uk/SealedCH.html
Choosing a Boiler FAQ http://www.makewrite.demon.co.uk/BoilerChoice.html
Gas Fitting Standards Docs he http://www.makewrite.demon.co.uk/GasFittingStandards