Mitsubishi EAHV-P – Monthly Chiller Maintenance Procedure

Perform this monthly checklist to maintain optimal performance of Mitsubishi EAHV-P screw vapor chillers used in commercial HVAC applications.

General System Overview

  • Thorough inspection of entire chiller system for leaks, corrosion, physical damage
  • Verify operating hours and compressor starts within expected monthly limits
  • Review complete alarm history for recurring issues or patterns
  • Inspect piping insulation integrity and support structures
  • Check equipment room ventilation and ambient conditions
  • Verify all safety signage and equipment labels are legible

Compressor & Oil System

  • Perform comprehensive compressor performance analysis
  • Oil sample collected and sent for laboratory analysis
  • Replace oil filter if pressure drop exceeds specifications
  • Test oil heater functionality and temperature regulation
  • Check oil separator efficiency and clean if necessary
  • Verify slide valve operation through full capacity range
  • Record vibration readings at multiple load conditions

Refrigerant System

  • Comprehensive leak detection using electronic methods
  • Verify refrigerant charge and adjust if necessary
  • Test and calibrate vapor injection system components
  • Replace filter driers if moisture indicators show contamination
  • Check superheat and subcooling at various load conditions
  • Inspect and test electronic expansion valve operation
  • Document refrigerant pressures and temperatures

Electrical System

  • Verify voltage, amperage, and frequency per specifications
  • Infrared scan of all electrical connections for hot spots
  • Test motor insulation resistance and record readings
  • Inspect and clean VSD cooling fans and heat sinks
  • Check starter contacts for pitting or wear
  • Verify proper operation of all control circuits
  • Test ground fault protection systems

Water & Cooling System

  • Analyze water quality for pH, conductivity, and treatment levels
  • Clean water strainers and document pressure drop
  • Verify flow rates and adjust balancing valves if needed
  • Inspect pump seals and bearings for wear
  • Test water flow switches and clean sensing elements
  • Check cooling tower operation and water distribution

Heat Exchangers

  • Measure and record approach temperatures for trending
  • Inspect tube sheets for signs of erosion or corrosion
  • Perform eddy current testing if fouling suspected
  • Clean heat exchanger tubes if approach exceeds limits
  • Verify refrigerant distribution in evaporator
  • Check gaskets and mechanical seals for leaks

Controls & Sensors

  • Calibrate all temperature sensors against known standards
  • Calibrate pressure transducers and verify accuracy
  • Update control software/firmware to latest version
  • Test all control sequences and staging operations
  • Verify BMS communication and data accuracy
  • Backup control parameters and settings

Safety & Protection Systems

  • Test all safety interlocks and document response times
  • Verify pressure relief valve settings and test dates
  • Test emergency shutdown from all activation points
  • Inspect rupture disks for damage or corrosion
  • Verify refrigerant monitor calibration and alarms
  • Test oil pressure and temperature safety controls

Performance Analysis

  • Calculate and record monthly average kW/ton efficiency
  • Compare performance against manufacturer baselines
  • Analyze energy consumption trends and patterns
  • Review capacity utilization and load profiles
  • Identify optimization opportunities and document
  • Verify vapor injection system efficiency gains

Documentation & Compliance

  • Complete detailed maintenance log with all findings
  • Update equipment history and maintenance records
  • File refrigerant usage reports per EPA requirements
  • Document all safety test results and corrective actions
  • Update preventive maintenance schedule based on findings
  • Generate monthly performance report for management