AC800

Common issues

• Fouling/scaling on the water or refrigerant side reducing heat transfer efficiency
• Brazed-joint leakage from thermal cycling fatigue over the unit's service life
• External corrosion of stainless plates/headers in a humid or salt-laden environment
• Partial flow blockage from debris or scale reducing capacity
• Freeze damage if the evaporator side runs with insufficient flow or too low a suction temperature
• Gasket/flange leaks at the pipe connections (not the brazed core itself)

Inspection checklist

• Trend the approach temperature (inlet/outlet delta-T) against the design/commissioning baseline to detect fouling
• Trend pressure drop across the unit against baseline
• Visually check for external leaks, frost patterns or staining that indicate an internal leak
• Check insulation condition and vapour barrier integrity
• Inspect connection flanges/gaskets and support brackets
• Confirm the unit's design pressure rating is not exceeded by current system operating pressure
• Check for external corrosion on shell, headers and connections
• Pressure-test after any intervention or suspected leak

Service intervals

Critical spares

• This is a brazed monobloc plate pack - the internal plates are not field-serviceable or individually replaceable, so the practical spare is a complete replacement unit
• Connection flange gaskets/O-rings
• Insulation/vapour barrier material for reinstatement after inspection
• Pressure relief device if fitted to the circuit, per the system design

Safety

• Refrigerant release hazard - asphyxiation/toxicity risk depends on the refrigerant type in this circuit, ventilate before working near a suspected leak
• High working pressure (unit rated up to 31 bar) - stored energy hazard, isolate and depressurise before opening connections
• Hot surfaces possible on the condenser side depending on service
• A brazed-core leak cannot be locally repaired - failure can mean sudden loss of the circuit rather than a gradual, isolable leak

Class survey

Depending on design pressure and internal volume, plate heat exchangers can fall under class pressure-equipment rules requiring periodic pressure testing or inclusion in the pressure vessel register - confirm this specific unit's classification status and keep the maker's data sheet/nameplate details on board for survey.