Trane Thermafit™ – Weekly Screw Vapor Chiller Maintenance Procedure

Use this checklist to perform weekly maintenance on Trane Thermafit™ screw vapor chillers for energy-efficient, reliable, and safe HVAC operations.

General System Overview

  • Thorough visual inspection for wear, corrosion, or physical damage.
  • Record and analyze operating hours and compressor starts.
  • Review alarm history for recurring issues or patterns.
  • Check insulation integrity on pipes and vessels.
  • Verify all safety guards and panels are secure.
  • Document any unusual sounds or vibrations.

Control System Review

  • Download weekly trend data from Tracer™ system.
  • Verify control setpoints match current load requirements.
  • Check sensor readings for accuracy and drift.
  • Test manual override functions.
  • Verify BAS communication status.
  • Document control response times and accuracy.

Screw Compressor Inspection

  • Monitor compressor for smooth operation and unusual sounds.
  • Check vibration levels and compare to baseline.
  • Verify slide valve operation through load range.
  • Monitor discharge temperature trends.
  • Check compressor current draw patterns.
  • Document capacity control response.

Oil System Check

  • Inspect oil level and color for contamination.
  • Check oil pressure differential.
  • Verify oil temperature within specifications.
  • Test oil heater operation and setpoint.
  • Check oil filter differential pressure.
  • Document oil consumption if any.

Refrigerant System Check

  • Measure and record operating pressures.
  • Calculate superheat and subcooling values.
  • Check sight glass for refrigerant flow.
  • Inspect for signs of refrigerant leaks.
  • Verify economizer operation (if equipped).
  • Document refrigerant performance trends.

Electrical Components

  • Inspect electrical connections for tightness and corrosion.
  • Check motor amperage against specifications.
  • Verify control panel displays and functionality.
  • Test control circuit voltages.
  • Check starter/VFD operation and cooling.
  • Inspect for signs of overheating.

Water Systems

  • Verify chilled water flow and pressure.
  • Check condenser water flow and temperature.
  • Clean Y-strainers and document debris.
  • Inspect pump operation and seals.
  • Test water treatment levels.
  • Verify flow switch operation.

Heat Exchanger Performance

  • Check approach temperatures and log trends.
  • Inspect for signs of fouling or scaling.
  • Verify temperature differential across coils.
  • Check for proper refrigerant distribution.
  • Document heat transfer efficiency.

Safety Systems Test

  • Test high/low pressure safety switches.
  • Verify temperature sensors and alarms.
  • Test emergency shutdown functionality.
  • Check oil pressure safety switches.
  • Verify flow switch interlocks.
  • Test relief valve operation indicators.

Performance Monitoring

  • Calculate and record weekly average kW/ton.
  • Review energy usage patterns and trends.
  • Analyze capacity vs.
  • Compare performance to design specifications.
  • Document runtime and cycling patterns.
  • Identify efficiency improvement opportunities.

Documentation & Reporting

  • Complete weekly inspection log with all findings.
  • Update maintenance tracking system.
  • Document any corrective actions taken.
  • Schedule follow-up maintenance as needed.
  • File water treatment test results.
  • Generate weekly performance summary.
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