7/11/2014

Maintenance Considerations chiller trane

Maintenance  Considerations
chiller trane


 
Maintenance chiller trane

 Centrifugal Water Chillers:
 
This period discusses general maintenance requirements of centrifugal water chillers. Although some of the information applies specifically to the design presented in this clinic, requirements for other centrifugal chiller designs are also included.

Maintenance Considerations
▲ Operating log
▲ Mechanical components
▲ Heat-transfer surfaces
▲ Fluid analysis
Once a centrifugal chiller is installed and put into operation, it usually continues to function without a full-time attendant. In many cases, the machine starts and stops on a schedule controlled by a building automation system or a simple time clock. The only daily maintenance requirement is to complete and review the operating log.
Water chillers are designed for maximum reliability with a minimum amount of maintenance. Like all large mechanical systems, however, certain routine maintenance procedures are either required or recommended.
 
operating log
ASHRAE Guideline 3
▲Chilled water inlet and outlet temperatures and pressures
▲Chilled water flow
▲Evaporator refrigerant temperature and pressures
▲Evaporator approach temperature
▲Condenser water inlet and outlet temperatures and pressures
▲Condenser water flow
▲Condenser refrigerant temperature and pressures
▲Condenser approach temperature
▲ Oil pressures, temperature, and levels
▲ Addition of refrigerant
▲ Addition of oil
▲ Vibration levels
Guideline 3, “Reducing Emission of Halogenated Refrigerants in Refrigeration and Air Conditioning Equipment and Systems,” is one of several advisory documents published by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE). This guideline includes a list of recommended data points to be logged daily for each chiller. Much of this data may be available from the display on the chiller control panel.
 
Special attention should be given to:
 
■    Reviewing the operating log and trends
■    Observing the oil pressure drop to determine if the oil filter needs to be replaced
■    Monitoring evaporator and condenser approach temperatures
■    Observing and recording the oil level
■    Monitoring purge pump-out operation

maintenance considerations
Mechanical Components

 
▲ Required maintenance
◆    Compressor and motor: no maintenance required
◆    Controls: no maintenance or calibration required
▲ Recommended maintenance
◆    Visually inspect overall unit
◆    Inspect safety controls and electrical components
◆    Tighten electrical connections
◆    Check for leaks

The compressor/motor assembly in direct-drive, hermetic compressor designs requires little periodic maintenance. The hermetic motor eliminates the need for external shaft seals associated with open motors. (These seals are a prime source of oil and refrigerant leaks and should be inspected on a regular basis.) Hermetic motor designs also eliminate the annual coupling and seal
inspections, alignment, and shaft seal replacement associated with open motors.
With the advent of microprocessor-based controls, the control panel and auxiliary controllers require no recalibration or maintenance. Remotely- mounted electronic sensors send information to the unit controller, which can be connected to a building automation system to communicate information and allow system-level optimization. These systems can notify the operator with an alarm or diagnostic message when a problem occurs.
As for any mechanical equipment, a daily visual inspection of the chiller is recommended to look for oil leaks, condensation, loosened electrical or control wiring, or signs of corrosion. Special attention should be given to safety controls and electrical components.
A qualified service technician should check the chiller annually for leaks. The United States Environmental Protection Agency (EPA) mandates refrigerant recovery whenever a refrigeration circuit is opened during the normal service of any air conditioning system.
 

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