FWN Self-Contained 20kW R134a

Common issues

• Refrigerant leakage at flare or braze joints over time, reducing cooling capacity
• Condenser fouling (seawater-cooled) from scale or marine growth, reducing heat rejection
• Compressor short-cycling from low refrigerant charge or faulty pressure switches
• Evaporator coil icing from low airflow or low refrigerant charge
• Seawater pump or strainer blockage reducing condenser cooling water flow
• Control board or thermostat sensor failure causing erratic operation
• Fan motor bearing wear increasing noise and reducing airflow

Inspection checklist

• Check refrigerant pressures against the maker's expected range for ambient/seawater temperature
• Inspect joints for oil staining indicating refrigerant leaks
• Check seawater strainer for blockage and condenser for scaling/fouling
• Verify condensate drain is clear and draining correctly
• Check compressor mounting, vibration isolators, and electrical connections
• Test high/low pressure safety switches and any freeze protection
• Check fan motor bearing noise and airflow across the evaporator
• Verify control panel alarms and thermostat calibration

Service intervals

Critical spares

• R134a refrigerant charge
• Compressor contactor/start relay
• High/low pressure switch
• Seawater pump seal kit

Safety

• Refrigerant under pressure - use proper recovery equipment, never vent to atmosphere
• Electrical hazard at compressor terminals - isolate before opening
• Seawater system under pressure - isolate before opening the strainer or pump

Class survey

HVAC units are not typically a dedicated class survey item unless tied to accommodation ventilation/fire-damper arrangements or serving safety-critical spaces such as the engine control room; surveyor interest is usually limited to fire damper integrity where ducting penetrates fire divisions.