5 Piping and Refrigeration Connections
WARNING! Risk of over-pressurization of the refrigeration system. Can cause explosive discharge of high-
pressure refrigerant, loss of refrigerant, environmental pollution, equipment damage, injury, or death. This
unit contains fluids and gases under high pressure. Use extreme caution when charging the refrigerant
system. Do not pressurize the system higher than the design pressure marked on the unit's nameplate.
CAUTION: Risk of excessive refrigerant line pressure. Can cause tubing and component rupture resulting in
equipment damage and personal injury. Do not close off the refrigerant-line isolation valve for repairs unless
a pressure-relief valve is field- installed in the line between the isolation valve and the check valve. The
pressure-relief valve must be rated 5% to 10% higher than the system-design pressure. An increase in
ambient temperature can cause the pressure of the isolated refrigerant to rise and exceed the system-design
pressure rating (marked on the unit nameplate).
NOTICE
Risk of oil contamination with water. Can cause equipment damage. Liebert® CRV systems require the use of
POE (polyolester) oil. POE oil absorbs water at a much faster rate when exposed to air than previously used oils.
Because water is the enemy of a reliable refrigeration system, extreme care must be used when opening
systems during installation or service. If water is absorbed into the POE oil, it will not be easily removed and
will not be removed through the normal evacuation process. If the oil is too wet, it may require an oil change.
POE oils also have a property that makes them act as a solvent in a refrigeration system. Maintaining system
cleanliness is extremely important because the oil will tend to bring any foreign matter back to the
compressor.
NOTICE
Risk of improper refrigerant charging. Can cause equipment damage. Refrigerant charge must be weighed into
air-cooled compressorized systems before they are started. Starting scroll and digital scroll compressors
without proper refrigerant charging can cause the compressors to operate at less than –15 °C (5 °F) evaporator
temperature and at less than 138 kPa (20 psig). Operation for extended periods at less than 138 kPa (20 psig)
can cause premature compressor failure.
5 Piping and Refrigeration Connections
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Vertiv™ Liebert® CRV CRD25 and CRD35 Row-Based Cooling System User Manual
