Describe how leaks are detected and rectified on a refrigerating plant, suction and discharge valves tested for tightness, and refrigerant charging carried out with illustration?

flowchart TD
    A[Refrigerant Cylinder] -->|Liquid/Vapour| B[Cylinder Valve]
    B --> C[Charging Manifold]
    C --> D[Liquid Valve]
    C --> E[Vapour Valve]
    E --> F[Charging Connection]
    F --> G[Compressor Suction Line]
    G --> H[Suction Valve]
    H --> I[Refrigeration Compressor]

• Leak detection: Halide detector, electronic detector, system leak test, shaft-seal test at different positions
• Rectification: Replace faulty seals/gaskets/valves, evacuate and re-test system
• Safety: Ventilate compartment, follow enclosed space entry, wear protective clothing
• Records: Log date, leak location, detection method, rectification, re-test results
• Valve tightness test: Isolate valve, pressurise to working pressure, monitor for 10–15 min, use detector
• Valve records: Log valve tested, test pressure, duration, result, action taken
• Charging connection: Compressor suction line
• Charging steps: Connect manifold, transfer refrigerant, heat cylinder indirectly (hot water), monitor sight glass
• Charging safety: Never heat cylinder directly, ventilate space, wear protective clothing
• Charging records: Log date, refrigerant type/quantity, cylinder details, initial/final pressures, observations