6.1 Refrigerant Piping and Charging
WARNING! Risk of explosive discharge from high-pressure refrigerant. Can cause injury or
death. This unit contains fluids and gases under high pressure. Relieve pressure before
working with piping.
WARNING! Risk of refrigerant system rupture or explosion from overpressurization. Can cause
equipment damage, injury or death. 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 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).
Consult local building and plumbing codes for installation requirements of additional pressure-relief
devices when isolation valves are field installed as shown in DPN002858 and DPN002808 (see Submittal
Drawings on page156). Do not isolate any refrigerant circuits from over-pressurization protection.
NOTE: The Liebert indoor cooling unit has a factory-installed high pressure safety switch in the high-
side refrigerant circuit. A pressure relief valve is provided with Liebert Lee-Temp™ condensers. Consult
your local building code to determine whether the Liebert MC or Liebert VFD condensers will require
field-provided pressure-relief devices. A fusible plug kit for Liebert VFD condensers is available for field
installation.
NOTICE
Risk of oil contamination with water. Can cause equipment damage.
Liebert 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.
Vertiv | Liebert CRV Installer/User Guide | 34
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