Heating & Water System Wiring

[Greenmantle]

In the process of replacing my standard wired programmer for a Smart Home unit.
I'm familiar with the 'S' Plan Wiring Diagram.
I have 2 room thermostats and hot water - so 3 channels.
The programmer is powered separately from a fused spur so power cable is not listed below.

Tracing through all my wires on the wiring centre I have the following:

(1) Programmer (2 wires) (one wire to both room thermostats, one wire to water tank thermostat).
(2) Upstairs Thermostat (4 wires)
(3) Labelled as Live (4 wires)
(4) Labelled as power (3 wires)
(5) Downstairs Thermostat (4 wires)
(6) Motorised Valve Downstairs (6 wires - white is redundant)
(7) Hot Water Tank Thermostat (3 wires)
(8) Motorised Valve Water (6 wires - white is redundant)
(9) Motorised Valve Upstairs (6 wires - white is redundant)
(10) Boiler (3 wires)
(11) Pump (3 wires)

All the earths are joined together.
The neutrals for (2)-(9) are joined together but the neutrals for pump and boiler are joined only to each other.
Also the lives for the pump and boiler are joined only to each other.
All other cables are correctly connected.

I am thinking that the boiler cable is providing a switched live source to the pump to control it (for example over running).
Am I correct?

[GasEngineer]

Very likely.

What make / model boiler do you have?

[Greenmantle]

GasEngineer said:

Very likely.

What make / model boiler do you have?

Potterton Suprima (obviously no opentherm and yes I know older than my teenage kids!)

[GasEngineer]

Yes - the Suprima has a pump overrun so the pump is powered directly from the boiler.

[MercmanSL]

You should have all the lives and neutrals coming from the same fused spur otherwise someone may unwittingly turn off one of the fused spurs and leave power still connected causing an electric shock, and possibly death.

[Greenmantle]

MercmanSL said:

You should have all the lives and neutrals coming from the same fused spur otherwise someone may unwittingly turn off one of the fused spurs and leave power still connected causing an electric shock, and possibly death.

Yep fully aware of that but unfortunately cannot do that since programmer and wiring centre is upstairs whilst boiler is by the back door.
Instead I have labelled programmer fused spur to say "now go and turn off boiler spur"