Central heating wiring

[KevinS]

Certain this topic has been covered loads of times - sorry
i have had very little experience of central heating wiring in the past, basically it was one person who did the vast majority of it, but now he has left the company and now it has fallen into my lap.
i can wire up systems but usually have to take it back to basics, ie take the wiring apart and trace the wires back then rewrire it up
i know this is the long way and I am certain it will get easier,
couple of weeks ago I had a fault which was giving me 240 at the room stat when it was calling for heat but 78v when it was not calling for heat - turned out to be the cylinder stat.
yesterday, I had a fault where the heating could be on, the hot water could be on, but not at the same time.

i have downloaded the wiring diagram from Honeywell, but still get stuck when something isn't working, do any of you guys have a flow chart or something so I can work out what the problem is in an easier methodical way

hope this makes sense. Any advice is better than what I currently have

i am also led to believe most of the systems are y plan, but some of the boilers have a pump over-run, how will I know this and is it blatantly obvious if the system isn't a y plan.

 

[telectrix]

look in tghe stickies. i think there's one with a link or a pdf for wiring diagrams

 

[KevinS]

Tel, can't see it in the stickies, cheers mate

 

[StuSpiers]

Try these I had them on my hub.

 

[SYKRAPS]

Hi Kev,

Generally speaking a y-plan has a 3 port diverter valve and s & c plans have a combination of 2 or more 2 port diverter valves, it may make more sense to you if you think of it all as a series of switches (which it is).

Switch 1 clock...........switch 2 room stat or cyl stat........switch 3 boiler stat.......and so on

If they are all closed the circuit in demand heats up but if 1 is open it doesn't.

Hope this helps.

Nige.