Daikin WHT – Monthly Chiller Maintenance Procedure

Use this checklist to perform monthly maintenance on Daikin WHT vapor absorption chillers to ensure performance, safety, and longevity.

Comprehensive System Assessment

  • Complete thorough visual inspection of entire absorption chiller system including vessels, piping, and insulation
  • Document all leaks, corrosion, cracks, or physical damage with photographs
  • Review operating hour logs and compare with manufacturer's service schedule
  • Test all alarm systems including high/low pressure, temperature, flow, and vacuum alarms
  • Verify insulation integrity and repair any damaged areas
  • Check all access doors, gaskets, and seals for proper closure

Detailed Solution Analysis

  • Draw solution samples from absorber, generator, and heat exchanger
  • Perform complete solution analysis.
  • Test corrosion inhibitor levels and add as necessary
  • Check for solution contamination, suspended solids, or discoloration
  • Verify solution pump performance including flow rates and discharge pressures
  • Document solution level trends and add makeup solution if required

Heat Exchanger Performance

  • Inspect all heat exchangers for fouling, scaling, or biological growth
  • Calculate and log approach temperatures for absorber, condenser, and evaporator
  • Check tube bundle cleanliness and schedule cleaning if necessary
  • Verify proper water box venting and no air accumulation
  • Test heat transfer efficiency against design specifications
  • Inspect eliminators and spray headers for proper operation

Vacuum System Testing

  • Perform comprehensive vacuum decay test with system isolated
  • Document purge unit run times and frequency over past month
  • Check purge pump oil level, color, and schedule oil change if needed
  • Test all vacuum gauges for accuracy using calibrated reference
  • Inspect vacuum breaker valves for proper seating and operation
  • Leak test all gaskets, seals, and valve packings

Electrical System Inspection

  • Inspect all electrical connections for tightness, corrosion, and overheating signs
  • Measure and record motor amperage for all pumps and verify against nameplate
  • Test motor insulation resistance using megohmmeter
  • Verify proper operation of all control circuits and interlocks
  • Check variable frequency drives (if applicable) for proper operation
  • Clean electrical panels and verify proper ventilation

Water Treatment & Chemistry

  • Perform complete water analysis for chilled and cooling water circuits
  • Check and adjust chemical treatment levels including biocides and corrosion inhibitors
  • Clean all water strainers and document debris accumulation
  • Verify chemical feed pump operation and calibration
  • Inspect cooling tower (if applicable) for biological growth
  • Document water consumption and check for excessive makeup water use

Control System Calibration

  • Calibrate all temperature sensors using certified reference thermometer
  • Verify pressure transducer accuracy and zero if necessary
  • Test all control valve actuators for proper stroke and response
  • Review and optimize control setpoints based on current load conditions
  • Download and analyze trend data for performance optimization
  • Update control system software/firmware if updates available

Performance Testing & Analysis

  • Conduct full-load performance test and calculate COP
  • Compare current efficiency with baseline and manufacturer specifications
  • Analyze heat input consumption trends and identify optimization opportunities
  • Review cycle temperatures and pressures for abnormal conditions
  • Document capacity degradation and schedule deep cleaning if needed
  • Create monthly performance report with recommendations

Safety Systems Validation

  • Test all safety interlocks and document response times
  • Verify crystallization prevention system including dilution cycle
  • Test emergency shutdown sequence from multiple initiation points
  • Check safety shower and eyewash stations for proper operation
  • Verify proper equipment room ventilation and gas detection systems
  • Review and update safety procedures and emergency contact information
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