FWN Self-Contained 75kW R134a

Common issues

• Refrigerant leakage at flare/brazed joints, gradually reducing cooling capacity
• Seawater-cooled condenser fouling/scaling, raising head pressure and reducing heat rejection
• Compressor short-cycling from low refrigerant charge or a faulty pressure switch
• Evaporator coil icing from low airflow or low refrigerant charge
• Seawater pump/strainer blockage causing a high condensing pressure trip
• Fan motor bearing wear causing noise/vibration in the air handling section
• Control system sensor drift causing erratic temperature control

Inspection checklist

• Check refrigerant charge/sight glass condition and leak-test the flare/brazed joints
• Measure suction and discharge pressures against expected values for R134a at the current seawater/ambient temperature
• Inspect and clean the seawater-cooled condenser tubes and strainer
• Check compressor oil level (where a sight glass is fitted) and listen for abnormal noise
• Verify safety cutouts (high/low pressure, motor overload) trip at the correct settings
• Inspect the evaporator coil and filters for fouling or icing
• Check fan motor bearings and belt/drive condition
• Verify control panel readings against a reference thermometer/gauge

Service intervals

Critical spares

• Compressor or compressor repair kit - Daikin-specific; confirm the exact spare with an authorised Daikin Marine service agent before ordering
• Refrigerant filter drier
• Condenser seawater pump seal kit
• Fan motor
• High/low pressure switches
• Liquid line solenoid valve

Safety

• R134a is a high-pressure refrigerant - use only rated recovery/charging equipment and avoid venting to atmosphere
• 440 V electrical supply - isolate and verify dead before opening the control panel
• Rotating fan/belt hazards - guards must be in place before running with covers removed
• Follow the vessel's confined space/ventilation procedure when working on refrigerant lines in an enclosed machinery space

Class survey

Accommodation/HVAC units generally sit outside strict statutory machinery survey scope unless the unit serves a safety-critical space (e.g., engine control room, battery space ventilation) - confirm applicability against the vessel's class notation before treating this as a survey item.

Estimated lifetime: Self-contained marine AC units of this type typically give 15-20 years of overall service, though the compressor itself often needs overhaul or replacement well before that (commonly in the 40,000-60,000 running hour range depending on duty and maintenance) - confirm against Daikin Marine's documentation for the FWN series.