Trade Practical and Project Work
What the practical exam asks
Typical jobs: pipe cutting, bending, swaging and flaring to tolerance; brazing a joint that passes a pressure test; wiring a split unit to the diagram; leak testing; evacuation; charging by weight and by superheat; measuring and recording; and fault finding on a trainer. The project is usually a small installation or a fault-diagnosis report supported by readings.
How marks are earned
Sequence and safety come first: PPE, isolation, correct tool selection. Then accuracy: a flare of the right size and not cracked, a bend without a kink (radius at least three to four times the pipe diameter for soft copper), torque to specification, vacuum below 500 microns. Then documentation: ambient, suction and discharge pressures, superheat, subcooling, current, voltage and final charge weight.
Worked example
The manual allows 5 m of pipe free and 20 g/m beyond that. Your run measures 11 m. Extra charge = (11 − 5) × 20 = 120 g. Record it on the job card, add it as liquid, and confirm with subcooling of 5–8 K at the condenser outlet.
Traps
Skipping the pressure test because the joint 'looked fine'; charging by guesswork without a scale; submitting a report with no measured values; and forgetting to refit insulation and covers before sign-off.