S plan heating system

[Rob brazendale]

Does this look something like just for c/h. As I add the extra zones in a just add a stat on the next free connector block

 

[PEG]

Out of interest,how are the two boilers twinned up?

 

[Toneyz]

As shown, but need an isolator to each boiler. Assuming that it is switched live, N&E to each boiler.

 

[Deleted account]

Are you a qualified sparky?

Separate these zones and the hot water system and draw it out should be easier to get your head round

Never a good idea to get advice on an Splan from a Yplan.

 

[Deleted account]

Never come across 2 boilers twinned up? Why would you do this?
Surely it would be better to have a couple of zones of one boiler and a couple of the other.

 

[Rob brazendale]

Two boilers in series. If there’s a Fault with one they still have heating and hot water. They have fitted a low loss header to the system aswell

 

[PEG]

Hi,surely you mean in parallel,with isolation? In series,would give the return/flow sensors,something to think about...

 

[Corbs]

Have a look at boiler sequencers

 

[davesparks]

Two boilers in series. If there’s a Fault with one they still have heating and hot water. They have fitted a low loss header to the system aswell

You didn't think to.mention the low loss header at the start of the thread then?

Based on this new information you will almost certainly have a boiler circulating pump which will need to be controlled by both boilers via a relay. This pump circulates water from the boilers into the low loss header.
The second pump will be circulating water from the low loss header and around the CH and DHW zones.

Worcester bosch will send you a wiring diagram of how to connect two of their boilers together if you give their tech support a call. It is important that you do this bit correctly otherwise you may damage the boilers or create a dangerous situation for anyone working on them in the future.

 

[PEG]

Have a look at boiler sequencers

....I have done...many,many times
This is why i know they are paralleled and not in series.

I did a two line post,hoping to get more detail,and Dave blew us out of the water with his thorough retort

These are systems and features,which are not added "ad-hoc",most generally specced and designed from the get-go. If this is the case,there will be system drawings for both the hydraulic and electrics.
If not,Dave's last paragraph is applicable.

 

[Rob brazendale]

Hey guys. I got this information off the plumber today, we’ve got 3 wireless programmers, 3 x 2 ports (heating) 1x 2 port for the cylinder,frost stat, 2 x secondary heating pumps (they’re the main system heating flows,stats will control these)2 x primary heating pumps (shunt pumps) cylinder stat, and secondary return hot water pump ,
2 x Worcester 40 cdi classics, 2 x grundfos 25/80 SF pumps, 2x grundfos 15/60 PR pumps, 3x Honeywell 2 port valves (heating) , 1 x Honeywell 2 ports (hot water circ) cylinder stat, frost stat and grundfos gold pump HWSR, #CONTROLS# 3 wireless single channel programmable room thermostats, 1 x wired hot water timer

 

[Rob brazendale]

I got this off Worcester today for linking the boilers

 

[Leesparkykent]

Are you using the frost stat for frost protection or as high limit for the header?

 

[Rob brazendale]

Frost peotection

 

[Leesparkykent]

Frost peotection

Have you got a pipe stat for the header or is there a high limit stat build in?

 

[Rob brazendale]

There isn’t one built in. We will have to get one.

 

[Leesparkykent]

It’s simple to wire if you break it down. It’s a lot of work to try and explain it or knock up a diagram. It might be easier if you do a diagram and I/we can tell you what needs changing etc if anything.

 

[Rob brazendale]

Appreciate that lee. I’ll post a diagram up tomorrow.