Connections And System Setup; Operating Conditions; Cooling, Humidification And Dehumidification; Heating - Liebert PX018 Installer's/User's Manual

3.3 Connections and System Setup

• The unit requires a drain, which must comply with all applicable codes. This drain line may
contain boiling water. See
details.
• Three-phase electrical service is required for all models. Electrical service must conform to
national and local electrical codes. See equipment nameplate for details.
• Plan the routing of wiring, piping and ductwork to the unit. Refer to the appropriate piping
connection location drawings, piping schematics, and electrical-connection drawings for your
system in
• Water/glycol and GLYCOOL units utilizing a drycooler may require an optional aquastat
setting. See Table 9.7 on page 89 and Table 9.8 on page 89 for drycooler aquastat setting
guidelines. Applications with the optional stat setting require field piping to be insulated to
prevent condensation.
NOTE: Seal openings around piping and electrical connection to prevent air leakage. Failure to do so
could reduce the unit's cooling performance.

3.4 Operating Conditions

The Liebert PDX/PCW must be operated in a conditioned space within the operating envelope that
ASHRAE recommends for data centers. Operating the PDX/PCW outside of this envelope can decrease
equipment reliability. Refer to ASHRAE's publication, "Thermal Guidelines for Data Processing
Environments."

3.4.1 Cooling, Humidification and Dehumidification

For operation in the Cooling, Humidification or Dehumidification modes, the Liebert PDX/PCW unit's
return-air requirements for proper unit operation are:
• Maximum dew point of 59°F (15°C).
• Minimum 68°F (20°C) DB.
• Maximum 85° (29.4°C) DB for humidification mode and maximum 100˚F (37.7°C) DB for cooling
and dehumidification modes.
NOTE: Operating some PDX units equipped with Thermal Expansion Valves (TXVs) above 80 to 85°F
(27 to 29.4°C) return air can cause the TXV to run out of stroke and result in an increase in superheat
(above 20˚F) thus limiting the unit's capacity.

3.4.2 Heating

For operation in the Heating mode, the Liebert PDX/PCW unit's return-air requirements for proper unit
operation are:
• Maximum dew point of 59°F (15°C).
• Maximum dry bulb of 80°F (27°C).
NOTE: Heating operation is not available when unit iCOM is set for Supply Air Control.
Vertiv | Liebert® PDX™ and PCW™ Installer/User Guide |
Field-installed, Gravity-fed Drain Line Requirements
Submittal Drawings on page 106.
on page 30, for
19