CD 2S Series – two-stage transcritical CO2 (e.g. CD2S300, CD2S360)

Valve inspection and replacement: suction and discharge reed valves are wear parts and must be checked for cracks, deformation, or seat damage at every major service interval.

Oil level and quality check: verify oil charge level via sight glass; sample oil for contamination, acid (TAN), and moisture content; change oil at recommended intervals.

Crankcase heater function: confirm heater is energised during standstill to prevent refrigerant migration into oil and liquid slugging at start-up.

Suction and discharge pressure/temperature monitoring: log operating conditions against published envelope to detect operating outside design limits (risk of overheating, liquid ingestion, or motor overload).

Motor winding insulation resistance (megohm test): measure insulation resistance to detect moisture ingress or winding degradation before it causes motor burnout.

Safety controls verification: test high-pressure cut-out, low-pressure cut-out, and motor thermal overload trips to confirm they operate within calibrated set-points.

Leak detection on shaft seals and service valves (open-type APE): check for refrigerant or oil leaks at all connections; inspect shaft seal face for wear on open-drive models.

Vibration and noise assessment: run compressor and compare noise/vibration signature to baseline to detect bearing wear, loose mountings, or valve flutter.