Common Guidelines For Optimum Chiller Performance

1. Maintain Equipment operating logs

• Logs should be filled out twice during each 8-hour shift
• Record pressures, temperatures, and other pertinent information to recognize performance
  deviations

2. Follow proper compressor shutdown and startup routines.

• Follow manufacturer recommended shutdown procedures
• Components that may need attention are the compressor, compressor motor, control center, purge
  unit, oil return system, cooler, condenser, starter, and water pumps
• Follow OSHA lockout/ tagout regulations

3. Check chiller control center and starter for proper operation

• Proper electrical overload settings
• Chiller shuts off promptly due to excessive amperage
• Check all starter wire connections for loose contacts, obstructions, or pitting
• Electronic controls for motor current limit, overload, power fault interruption, and pre-rotation vane
  control (centrifugal chillers) should be tested

4. Perform oil sampling and analysis

• Oil analysis provides unambiguous evidence of chiller condition
• High copper levels indicate tubing corrosion, or oil pump bearing wear
• HVAC manufacturers recommend annual oil sampling and filter inspection

5. Keep Refrigerant clean and charged

• Condenser and evaporator shells become subject to corrosion
• Rust can settle in condenser shell, mix with oil, and become sludge
• Sludge-covered tubes reduce heat-transfer efficiency, raising energy consumption

6. Eliminate Condenser tube scale

• Excess head pressure caused by scale makes the compressor work harder
• Mechanical brush cleaning of tubes is recommended if scale buildup is a problem

7. Maintain Condenser water flow rate

• Eliminate scale buildup in the condenser tubes
• Check valves for proper functioning
• Check for clogged nozzles in the cooling tower, dirty water strainers, air in the water piping

8. Eliminate excess air

• Review operating logs to determine refrigerant pressure
• Air must be purged because it increases head, forcing the compressor to work harder
• Check automatic purge unit for proper operation

9. Maintain Motor efficiency

• Motor must be kept clean and cool
• Motor improperly cooled if logs show increase in current draw without voltage increase
• Megohmmeter all leads, terminal lugs, and wire connections
• Bolts holding the motor in place should be tight
• Lubricate bearings

10. Test Heat-Exchanger tubes

• Outsource Eddy current testing and analysis