Mitsubishi EACV – Weekly Water-Cooled Chiller Maintenance Procedure

Use this weekly checklist to ensure optimal operation and reliability of Mitsubishi EACV water-cooled chillers.

General System Overview

  • Inspect for leaks, corrosion, or damage to pipes, insulation, and supports.
  • Record compressor runtime and start count for the week.
  • Review alarm status and historical logs from the past week.
  • Check for any unusual conditions or changes since last inspection.
  • Verify all access panels are secure and properly sealed.

Compressor & Refrigerant System

  • Check for abnormal noise, vibration, or heat from compressor.
  • Verify refrigerant suction and discharge pressures are within range.
  • Oil Level:Check oil sight glass and ensure proper oil level(Oil-lubricated models only).
  • Oil Heater:Confirm oil heater operation and proper standby temperature(Oil-lubricated models only).
  • Check refrigerant sight glass for proper charge indication.
  • Record superheat and subcooling values for trending.

Electrical System

  • Check terminal tightness, corrosion, and discoloration.
  • Log motor amperage and verify against specifications.
  • Confirm proper operation of control panel and indicators.
  • Check starter contacts for pitting or wear.
  • Verify phase voltage balance within 2%.
  • Test control circuit voltage and operation.

Water Circulation System

  • Measure chilled and condenser water flow, pressure, and delta-T.
  • Inspect pump operation, check for abnormal noise or vibration.
  • Inspect cooling tower: clean basin, check float valve and fan operation.
  • Verify water flow switches are functioning properly.
  • Check expansion tank pressure and operation.
  • Inspect piping for vibration or support issues.

Heat Exchange Components

  • Inspect condenser and evaporator coils for fouling or scale.
  • Log approach temperature and compare to specifications.
  • Clean coils if heat transfer performance is degraded.
  • Check refrigerant-to-water temperature differentials.
  • Verify proper water velocity through tubes.
  • Inspect tube sheets for signs of corrosion.

Water Treatment

  • Verify dosing pumps are operating and chemical levels are correct.
  • Test pH, hardness, and TDS levels.
  • Clean strainers or replace filters as needed.
  • Check blowdown operation and conductivity levels.
  • Verify biocide treatment schedule is being followed.
  • Inspect chemical feed tanks and refill as necessary.

Safety & Protection Systems

  • Check pressure relief valves and interlocks for proper operation.
  • Verify shutdowns trigger properly (temperature/pressure limits).
  • Ensure emergency stop buttons and LOTO tools are accessible.
  • Test flow switches and verify proper setpoints.
  • Check refrigerant monitor and leak detection systems.
  • Verify all safety labels are legible and in place.

Performance Monitoring

  • Record kW/ton ratio and compare with efficiency goals.
  • Review temperature and pressure trend logs for the week.
  • Flag and escalate any significant anomalies or trends.
  • Calculate weekly average efficiency and document.
  • Compare current performance with seasonal baselines.
  • Identify opportunities for optimization or adjustment.

Documentation

  • Complete weekly checklist log with date and technician name.
  • Attach trend reports or alarm summaries as needed.
  • Ensure compliance with OSHA, ISO 9001, 14001, and 50001.
  • Update maintenance tracking system with findings.
  • Document any corrective actions taken or needed.
  • Schedule follow-up actions for identified issues.