S-Plan · wiring diagram
Wireless S-Plan wiring diagram
In short
An S-Plan is a fully pumped heating system with two 2-port motorised zone valves, one for central heating and one for hot water, driven by a programmer, a room thermostat and a cylinder thermostat. Each valve’s end switch feeds the boiler’s switched live, so the boiler fires only while a valve is open: the boiler interlock.
An S-Plan with a two-channel wireless thermostat and its receiver in place of the programmer and room stat.
This circuit, wired in the simulator. Wire colours as the lessons teach them. The meter reads what the circuit is doing.
The wiring centre, block by block
A block is a plain conductor: every wire landed on it is joined to every other, and to nothing else. The numbers are the habit the DrawWarm Method teaches, so the next engineer can read your work.
| Block | As the lessons teach it | Wired here |
|---|---|---|
| 1 | Permanent live from the fused spur, and both valves’ greys | Fused Spur L, Heat-Only Boiler L, 2-Port Valve (hot water) G, 2-Port Valve (heating) G, Wireless Receiver 2Ch L |
| 2 | Neutral | Fused Spur N, Circulation Pump N, Heat-Only Boiler N, 2-Port Valve (hot water) N, 2-Port Valve (heating) N, Wireless Receiver 2Ch N |
| 3 | Earth | Heat-Only Boiler E, 2-Port Valve (hot water) E, Fused Spur E, Circulation Pump E, 2-Port Valve (heating) E, Wireless Receiver 2Ch E |
| 5 | The room thermostat’s call, out to the heating valve’s brown | 2-Port Valve (heating) B, Wireless Receiver 2Ch 4 |
| 6 | Hot water demand from the programmer, out to the cylinder thermostat | Cylinder Thermostat C, Wireless Receiver 2Ch 3 |
| 8 | The cylinder thermostat’s call, out to the hot water valve’s brown | 2-Port Valve (hot water) B, Cylinder Thermostat 1 |
| 10 | The valves’ oranges in, the boiler’s switched live out | 2-Port Valve (hot water) O, Heat-Only Boiler SL, 2-Port Valve (heating) O |
Every wire, terminal by terminal
| From | Terminal | To | Terminal | Colour |
|---|---|---|---|---|
| Heat-Only Boiler | PL | Circulation Pump | L | Brown (live) |
| Heat-Only Boiler | E | Wiring Centre | 3 | Green/yellow (earth) |
| 2-Port Valve (hot water) | E | Wiring Centre | 3 | Green/yellow (earth) |
| Fused Spur | E | Wiring Centre | 3 | Green/yellow (earth) |
| Fused Spur | N | Wiring Centre | 2 | Blue (neutral) |
| Circulation Pump | N | Wiring Centre | 2 | Blue (neutral) |
| Heat-Only Boiler | N | Wiring Centre | 2 | Blue (neutral) |
| 2-Port Valve (hot water) | N | Wiring Centre | 2 | Blue (neutral) |
| Fused Spur | L | Wiring Centre | 1 | Brown (live) |
| Heat-Only Boiler | L | Wiring Centre | 1 | Brown (live) |
| 2-Port Valve (hot water) | O | Wiring Centre | 10 | Orange |
| Cylinder Thermostat | C | Wiring Centre | 6 | Grey |
| 2-Port Valve (hot water) | B | Wiring Centre | 8 | Brown (live) |
| 2-Port Valve (hot water) | G | Wiring Centre | 1 | Grey |
| Circulation Pump | E | Wiring Centre | 3 | Green/yellow (earth) |
| Heat-Only Boiler | SL | Wiring Centre | 10 | Orange |
| Wiring Centre | 8 | Cylinder Thermostat | 1 | Brown (live) |
| 2-Port Valve (heating) | B | Wiring Centre | 5 | Brown (live) |
| 2-Port Valve (heating) | G | Wiring Centre | 1 | Grey |
| 2-Port Valve (heating) | O | Wiring Centre | 10 | Orange |
| 2-Port Valve (heating) | E | Wiring Centre | 3 | Green/yellow (earth) |
| 2-Port Valve (heating) | N | Wiring Centre | 2 | Blue (neutral) |
| Wireless Receiver 2Ch | E | Wiring Centre | 3 | Green/yellow (earth) |
| Wireless Receiver 2Ch | L | Wiring Centre | 1 | Brown (live) |
| Wireless Receiver 2Ch | N | Wiring Centre | 2 | Blue (neutral) |
| Wireless Receiver 2Ch | 4 | Wiring Centre | 5 | Brown (live) |
| Wiring Centre | 6 | Wireless Receiver 2Ch | 3 | Grey |
Where it connects
Other systems
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If this is your home: this page is written for heating engineers. Mains wiring and gas appliances are not DIY jobs; call a Gas Safe registered engineer. If you smell gas, leave the building and call the National Gas Emergency Service on 0800 111 999.
Practise it in the simulator.
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