NOT a mid position valve.

[Obi]

Hi all, first post so be gentle

I removed a hideous old timing unit and replaced with a snazzy new (eBay) Drayton Tempus 7 allowing for the first time, independent control of hot water and central heating but I fear that I've made a boo boo in the wiring. I won't go into depth about what it looks like now, but I will show what I think I should have minus the bit I'm stuck on.

View media item 26967
Shown above is the live connections through the system. You'll notice that the poor old valve is left out of the equation.

At present the valve is powered by connecting B to C but of course this means that I only have heating when the water is timed on, but not demanded.

Perhaps I cannot do this with the valve I have, maybe I need a 3 port Mid-position. What I'd like to have is independently timed but if two demands collide, HW takes precedence.

I hope this all makes sense. Please help!

 

[Obi]

Wups, I think the boiler is actually wired through the pump to avoid it firing if the pump breaks. Sorry, can't be bothered to fix the pic as it's not really important.


..or is it?!

 

[seco services]

what valve do you have now if you think you need a mid position valve ?

 

[twgas]

try this:
http://wiki.diyfaq.org.uk/index.php?title=Image:W-Plan-Wiring.gif

but you'll also need to connect HW off (prog) to No 5 (terminal strip), and your diagram is not much use to anyone

 

[Obi]

Thanks for the quick replies!

Mick: Seems perfect, I've googled for that very pic so many times, but I've been looking at Y-plan, not W-plan. The only thing I knew was that mine wasn't S-plan!

Seco: it's a Honeywell 3 port (but NOT mid position) valve, I now know it to be aka a "Divertor" valve, as per Mick's linked pic.

I'll give that a blast in the week and let you know how I get on!