Honeywell S plan woes

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I'm new to this, so don't get angry if I appear a bit dumb!

Basically, I am having a new boiler fitted, but to save me some money, I am doing the wiring work myself, which will be throughly checked by a qualified person when he also replaces my fusebox for a modern one, so everything will be quite legal!

My problem is this: I have altered the pipework to have a 2 zoned heating area, wired as per the Honeywell S plan wiring diagram. [ My pipework is all 28mm, so I have also disregarded the white wire & isolated it, as per Honeywell's note on the paperwork thatcame with the zone valves.]
BUT, I could not buy a Honeywell progra mmer, so instead I bought a Horstmann C21 Centaur.

I used a Honeywell 10 way wiring box in accordance with the S plan wiring diagram, so everything is wired - correctly - into that. I have also taken a power supply from that unit, to the new Horstmann programmer unit.

So, my question is this, the Horstman unit does not have the same wiring number configuration to that of the Honeywell unit. I realise that I cant just have the programmer wired with just a power supply, so do I take it that I will also have to wire the programmer into the 10 way junction box too. To me, this is then duplicating everything, so do I need to do this?


Thanks for any help gents!
 
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Yes. How else will the programmer 'talk' to the rest of the system otherwise? Valves, stat, boiler, .......Do you mean how do i wire it?
 
Yes. How else will the programmer 'talk' to the rest of the system otherwise? Valves, stat, boiler, .......Do you mean how do i wire it?

Thanks, thats what I thought. So I will need to connect the programmer to the junction box. For example, using Horstmann's wiring diagram, No 4 connects to the room stat [I am looking at their No 7 example, " Fully pumped system using roomstat, clyinder stat & two [2port] motorised valve with auxiiary switches]

So do I take it then that I wire this no 4 tothe relevant connection in the 10 way box, and carry on doing the same with all the others?

I am still worried about the other upstairs room stat though. I am correct in thinking that by connecting it to No.4 as per the other one, this stat will fire up the zone valve for that floor without conflicting the otehr zone vale? I guess thats the whole idea of individual stats, but I thought I'd ask!

Many thanks for your patience!
 
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if you have a S PLAN then you will have 1 zone valve for your room stat (HEATING) and 1 zone valve for your cylinder stat (HOT WATER).

THese will be connected up differently, eg the room stat call will not be connected to the cyl stat call terminal in the wiring centre!!
 
if you have a S PLAN then you will have 1 zone valve for your room stat (HEATING) and 1 zone valve for your cylinder stat (HOT WATER).
That is assuming that he has a heat only boiler, not a combi.

In any case, what the OP is wanting to do is an "S plan plus" (with or without the HW part) i.e. more than one heating zone.
 
yes a S PLAN plus with 2 or more heating zones. same thing though, you wouldn't connect different room stats to the same zone valve! they'd be separate connections to each zone valve!

also with a combi system the diverter valve is built into the boiler casing so it is very unlikely to have a motorised valve somewhere on the pipeline??
 
yes a S PLAN plus with 2 or more heating zones. same thing though, you wouldn't connect different room stats to the same zone valve! they'd be separate connections to each zone valve!
Agree, I was not suggesting they were connected to the same stat. I was just pointing out that you assumed the OP had a heat only boiler and therefore needed a tanks stat etc.

also with a combi system the diverter valve is built into the boiler casing so it is very unlikely to have a motorised valve somewhere on the pipeline??
But we still do not know what boiler the OP is installing; maybe he does not know himself ;)

The important thing is that the Honeywell and Horstman S-plan diagrams assume that the boilers need 230v switched via the zone valve. If they require volt-free switching, the diagrams are wrong and need modifying.
 
I agree, the boiler manufacturers instructions are most important when wiring up. but what exactly is volt-free switching?!! never heard of that before.

one point i was just thinking-probably just me being dumb today !:) in a normal y plan the orange wire HAS to have voltage to allow the pump/boiler to run when heating and heating/ & h/w are on. If there is no voltage to orange does this mean the motor has also failed, as it would if no voltage was on the white wire when heating was calling ... ??
 

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