Intermediate · Unit 9 · Written and being checked
Commissioning
In short
The last job on a new system: the dead tests first - every earth, the short-circuit check - then the supply, its polarity and every state of a three-zone S-Plan Plus in turn, with the interlock and the pump's overrun; the controls proven - time control, temperature control and the interlock; the controls shown to the customer; and a practical on a system you have not seen. This unit is written and being checked; it opens to learners when it is ready.
In this unit
Dead tests first
A new S-Plan Plus as the installer left it, the spur off: proved dead at the wiring centre, the boiler's and the pump's boxes opened, earth continuity from the spur's earth to the boiler, the pump and the three zone valves, then the live to the neutral and to earth on ohms.
How it opensCOMMISSIONING is the last job on a new or changed heating system. You prove the system is safe, then prove it works, before the customer relies on it.
Every state, live
The same S-Plan Plus switched on: the supply and its polarity at the wiring centre, then the truth table in order - nothing wanted, zone 1 alone, zone 2 alone, the hot water alone, everything, and everything satisfied with the programmer's heating and hot water both on (the interlock) - the pump's overrun watched, block 10 read at 230 V and at 0 V.
Proving the controls
The controls proven one at a time on the S-Plan Plus: time control and temperature control to the heating, then to the hot water, and the boiler interlock read with the meter.
Handing over
The S-Plan Plus's controls shown to its customer: the spur, the programmer, each zone's room stat, the cylinder stat and why it stays at 60 °C, the boiler's screen, and the system left set as the customer wants it.
The practical: commissioning an unseen system
A new three-zone system you have not seen - a system boiler with its pump inside, a programmer based on the Danfoss FP715Si, a stat based on the Honeywell T6360B, a cylinder stat based on the Drayton HTS3, three zone valves, laid out its own way - commissioned from your checklist: proved dead, every earth, the short-circuit check, the supply and its polarity, every state, the interlock and the overrun. No hints. Recorded.
The practical · recorded, no hints
You will learn to
- Commission a system in a fixed order, the dead tests first, and write each result down as a checklist
- Test earth continuity from the supply's earth to every part, and check the live for a short circuit to the neutral and to earth
- Prove the supply and its polarity, then every state of a three-zone system in turn: each zone alone, the hot water alone, everything, and nothing
- Prove the boiler interlock, and watch the pump's overrun
- Prove time control and temperature control, for the heating and for the hot water
- Hand the controls over: show the customer each one, let them try it, and leave it set as they want
- Commission a system you have not seen, with branded parts, from your checklist alone
Checks and credit
- A timed check at the end of the unit, its questions drawn at random. The score goes on your record.
- A practical with no hints, every step recorded.
Where it connects
The parts it uses
Wiring diagrams
Intermediate
- Actuator anatomy
Unit 8, before this one
Back to the Programme.
Read the explanation
- What a truth table proves when you commission a heating system
Commissioning proves every state of the controls before handover. The truth table’s rows, the boiler interlock row by row, and the dead tests that come first.
Practise it in the simulator.
Runs in the browser on a laptop or desktop. Cancel any time.