S Plan Plus Heating System

[snipes]

hello,

just been looking on the net for a bit of support on this matter as i carnt get in touch with honey well or vaillant about it . then came across this site and thought i would post ! so hello to all .

iam a qualified electrician wanting an answer to a question on the title above .

the boiler is a vaillant eco tec system it requires a live feed at all times fed from a fuse spur the there is 3 control terminals 3,4,5 . 5 is spare neutral so not bothered about that . 4 is switch live from terminal 10 on wiring block and orange wire on the valves, but what gets connected to 3 ? nothing ? perminate live ? and if so can this be linked form the live feed ? not done many system boilers always seem to be combi

thanks in advance for the replays

this is the wiring diagram for a s plan if it helps

 

[banny07]

hope his helps . posted by Lenny a few days ago
http://www.electriciansforums.net/e...cal-forum/11718-central-heating-diagrams.html

 

[fog]

Hi there
do plenty of boiler wiring, friend is b****y plumber he actually gives me plenty of work!
I often have to provide a permanent live for frost stats on outside boilers etc.
I take the permanent live after the 3 amp fused spur which feeds the ten block connector on terminal number 1. of connector block 3. on your drawing is usually the earth connections

 

[bramboy]

Hi all... Do quite a few s-plans. Majority of boiler manufactures recommend you take your mains to boiler first. Then terminal 3 is perm live, terminal 4 is switch live and termnal 5 neutral. Isolation to all external controls time clocks and valves can be turned off via switch on boiler front.
System boilers external switch contacts are exactly the same as a combi boilers (usually )

Good thing to remember on 2 port valves, whether its upstairs, downstairs heating and underfloor heating is to join all greys together, all oranges together. Then use brown on valve from switched live signal (ie room stat) to switch the valve. All the brown does when made live is open the valve and makes a ciruit between orange and grey(micro-switch).

Some boilers 3 and 4 so to speak operate at low voltage (ariston).....These two port micro-switches
(grey and orange) can switch at low volt, but brown still needs to be switch signal at 230volts. This is not ideal on the valve flex having these different volages. This info was from ariston technical( the boiler in genral wasn`t any cop)

Bit of a mouthful that!

 

[snipes]

thanks for the replays , i mignt not have explained myself very clearly

all the wiring on the system is in and all the controls are working fine , all my question is , when you take the link out of terminals 3 and 4 if you look at the diagram you just have a switch live coming from terminal 10 on the connection blocks. so if you connect the switch live to terminal 4 is that it ? dont you need anything connected to terminal 4 ?

the whole of the system is 240v there is no low voltage or no volt contacts

this is the link for the user guild page 28 http://www.vaillant.co.uk/stepone2/data/downloads/d7/42/00/839592_09.pdf

the diagram is not quite right as it has an external pump and the pump is inside the boiler in the vaillant thats the bit iam unsure about

thanks

 

[bramboy]

Number 1 on your 10 way block to number 3 on boiler (remove perm live)
Number 10 on your 10 way block to number 4 on boiler



Hope this helps

 

[snipes]

thanks you for quick the replay

can you just link the live in the boiler to terminal 3 ?as that is just the same as terminal 1 and is disconected from the same dp switched spur

 

[bramboy]

Hi..
In an ideal world your live feed to your valves should be terminal 3. If the wiring is already in place just put that switch live into terminal 4 on boiler from number 10 on your wiring box and don`t connect anything into 3 and 5.

Good luck.

 

[Tony_spark]

Generally speaking what Size cable would you use for an S plan heating system? I know you would run 2.5 from the D/B to the Spur feeding the system. Would I use 2.5 for the rest of the system?

Cheers

 

[snipes]

Hello,
I use 1.5 for the whole install ,even the supply and back it up at the dis- Board with a 6a the boiler usually requires a 3a bs88 fuse so why supply the spur with 16 of 20amp when it's not needed. saves on cable too.

 

[skirby]

I know this is a bit late to help Snipes but here is an explanation and wiring diagram about wiring S Plan and central heating boiler systems. Wiring Diagram for S Plan Zoned Central Heating Systems | Electrician's Blog It may be useful to someone else in the future. All the best.