S plan heating system

[Rob brazendale]

It’s all been plumbed up. I’ll draw up a diagram and post it on here. Cheers

 

[Rob brazendale]

It’s ok been plumed in. Cheers I’ll draw up a diagram and post it on here. Thanks

 

[Leesparkykent]

It’s ok been plumed in. Cheers I’ll draw up a diagram and post it on here. Thanks

What are the two pumps for?

 

[Toneyz]

What are the two pumps for?

This is what I was trying to find out from the OP, Lee we think one is for the system and the other is for secondary return but waiting for the OP to confirm from the plumber.

 

[Leesparkykent]

If it’s a secondary return it should be obvious as it will be plumbed into the cylinder secondary return...The pump will have bronze or SS impellers and the housing is usually yellow if it’s a grundfos pump.

 

[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.