Refrigerant Piping And Charging - Liebert PX018 Installer's/User's Manual

5.2 Refrigerant Piping and Charging

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. Local building or plumbing codes may require
installing a fusible plug or other type of pressure-relief device in the system.
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).
When field-installed isolation valves are used, consult DPN002929 and DPN003843, included in
Submittal Drawings
protection.
Consult local building and plumbing codes for installation requirements of additional pressure-relief
devices when isolation valves are field installed. 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. Consult local building codes to determine whether the Liebert MC Condensers
without receivers will require field-provided pressure-relief devices such as a fusible plug. A pressure-
relief valve is provided with Liebert Lee-Temp™ receivers and an integral, fusible plug is provided on
PDX-EEV unheated receivers.
NOTICE
Risk of oil contamination with water. Can cause equipment damage.
Liebert PDX 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® PDX™ and PCW™ Installer/User Guide |
on page 106. Do not isolate any circuits from over-pressurization
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