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Red Seal Refrigeration & AC Mechanic study materials
Red Seal Refrigeration & AC Mechanic study resources

Red Seal Refrigeration & AC Mechanic: System Installation, Commissioning, and Start-Up

Red Seal Refrigeration & AC Mechanic · Work through your exam, one topic at a time.

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System Installation, Commissioning, and Start-Up

Installation, Commissioning and Start-Up tests whether you can turn a pile of equipment into a code-compliant, documented system that runs to specification. Items cover equipment placement and clearances, piping and electrical connection, pressure testing, evacuation, charging method, control settings and handover.

Before energizing

  • Verify clearances for airflow and service, anchoring, and seismic restraint where required; confirm vibration eliminators and flexible electrical connections are fitted.
  • Confirm relief valves are piped and sized as CSA B52 requires, and that machine rooms have the ventilation and detection the code demands.
  • Crankcase heaters must be energized for 24 hours before start on many compressors so refrigerant is driven out of the oil.
  • Check three-phase rotation before the compressor runs.

Evacuation and charging

  • Pressure test with dry nitrogen, then evacuate with a two-stage pump to 500 microns or lower. Triple evacuation breaks the vacuum with nitrogen to sweep moisture.
  • Isolate the pump and perform a standing vacuum test: a rise from 500 microns past about 1000 in ten minutes means a leak or remaining moisture.
  • Charge by weight for critically charged systems (capillary and small packaged units), by subcooling for TXV systems, and by superheat for fixed-orifice systems, following the manufacturer's stated method.

Worked example: TXV superheat

Suction pressure gives a saturation temperature of 4°C and the suction line reads 15°C. Superheat = 11 K against a target of 6 K, so the valve is feeding too little. Open it counterclockwise about half a turn, allow 15 minutes to stabilize, then recheck. Subcooling should stay at the manufacturer's value, typically 5–8 K.

Documentation

Record ambient and space temperatures, pressures, superheat, subcooling, amp draws against nameplate, static pressure and airflow, control setpoints, and any charge added. Handover includes filter sizes, belt part numbers and warranty requirements.

Traps

  • Starting a system before evacuation because the schedule is tight.
  • Charging vapour into a blend system.
  • Adjusting a TXV and reading results immediately, before the system stabilizes.
  • Skipping the rotation check on a scroll compressor.