9/17/2015

Maintenance Considerations of Water Chillers chiller trane party 1

Maintenance Considerations
of Water Chillers chiller trane
party 1


Maintenance Considerations




Maintenance Considerations:

 This period discusses general maintenance requirements of helical-rotary water chillers. Although some of the information applies specifically to the design presented in this clinic, requirements for other helical-rotary chiller designs are also included.
 
Maintenance Considerations
Once a helical-rotary 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 the building automation system or a simple time clock. The only daily maintenance requirement is to check 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:
Operating log
▲  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
▲ Compressor refrigerant suction and discharge temperatures
▲ Refrigerant level
▲ Oil pressures, temperature, and levels
▲ Addition of refrigerant
▲ Addition of oil
▲ Vibration levels
 The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) has published Guideline 3 titled Reducing Emission of Halogenated Refrigerants in Refrigeration and Air Conditioning Equipment and Systems.
This guideline includes a recommended list of data points to be logged daily for each chiller. Much of this data may be available through the chiller’s control panel.
Special attention should be given to the following:
■    Review the operating log and trends
■    Measure the oil pressure drop to determine if the oil filter needs to be replaced
■    Measure refrigerant superheat and subcooling
■    Measure both the refrigerant and oil charges

Mechanical Components:
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
◆    Test vent piping
Direct-drive, semi-hermetic compressor designs require no periodic maintenance on the compressor/motor assembly. The compressor contains only 3 main moving parts: the male and female rotors and the slide valve. The semi-hermetic motor eliminates the need for external shaft seals associated with open motors. These seals are a prime source of oil and refrigerant leaks. It also eliminates annual coupling and seal inspections, alignment, and shaft seal replacement.
With the advent of microprocessor-based controls, the control panel and auxiliary controllers require no recalibration or maintenance. Remote-mounted electronic sensors send information to the unit controller, which can be connected to a building automation system in order to communicate information and allow for system-level optimization. These systems can notify the operator with an alarm or diagnostic message when a problem occurs.
Like 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 the safety controls and electrical components.
It is recommended that a qualified service technician check the chiller annually for leaks. In the normal service of any air conditioning system, the Unites States EPA mandates that whenever a refrigeration circuit is opened, recovery of the refrigerant is required.
Finally, the vent piping of all pressure relief valves should be leak-tested annually for the presence of refrigerant to detect improperly sealed valves. Leaking relief valves should be replaced.

                                                                         younes kandi

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