Vertiv Liebert DSE, System Design And User Manual

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5 PRE-INSTALLATION PREPARATION AND GUIDELINES
NOTE: Before installing unit, determine whether any building alterations are required to run piping,
wiring and ductwork. Follow all unit dimensional drawings and refer to the submittal engineering
dimensional drawings of individual units for proper clearances.
Refer to Table 2.2 on page 11, and submittal drawings to determine the type of system being installed
and anticipate building alterations, piping and ductwork needed.
The unit dimensions, pipe-connection locations, and piping schematics are described in the submittal
documents included in the Submittal Drawings on page 67.
• Verify that the floor is level, solid and sufficient to support the unit. See Shipping Dimensions
and Unit Weights on page 21 for unit weights.
• Confirm that the room is properly insulated and has a sealed vapor barrier.
• For proper humidity control, keep outside or fresh air to an absolute minimum (less than 5% of
total air circulated in the room).
• Do not install a Liebert® DSE in an alcove or at the end of a long, narrow room.
• Install the units as close as possible to the largest heat load.
• Allow at least the minimum recommended clearances for maintenance and service. See the
appropriate submittal drawings for dimensions.
We recommend installing an under-floor water detection system. Contact your Vertiv representative for
information.
5.1 Planning Dimensions
The indoor and heat-rejection unit dimensions are described in the submittal documents included in the
Submittal Drawings on page 67.
5.2 Connections and System Setup
• The unit requires a drain, which must comply with all applicable codes. This drain line may
contain boiling water. See Field-installed, Gravity-fed Drain Line Requirements on page 38, for
details.
• If seismic requirements apply, consult your Vertiv representative for information about a
seismic-rated floor stand.
NOTE: Seal openings around electrical connection to prevent air leakage. Failure to do so could reduce
the unit’s cooling performance.
The DSE controls superheat with an electronic expansion valve (EEV). The EEV controller adjusts the
orifice based on suction pressure and temperature. The EEV control will drive the valve to maintain the
superheat setpoint, set in the Liebert® iCOM, using a Proportional, Integral, Derivative (PID) routine. The
PID control values are set at the factory for most applications. These default values PID will allow stable
superheat control of the unit.
5.3 Operating Conditions
The Liebert® DSE must be operated in a conditioned space within the operating envelope that ASHRAE
recommends for data centers. Operating the DSE outside of this envelope can decrease equipment
reliability. Refer to ASHRAE’s publication, “Thermal Guidelines for Data Processing Environments.”
The recommended maximum for return-air temperature is 105°F (40°C) and maximum dew point is 59°F
(15°C). The recommended minimum return-air temperature setpoint for the DSE is 85°F (29.4°C).
5.3.1 Humidification Control
The humidifier option is not available on the DA250. A remote humidifier contact is available for a stand-
alone humidifier.
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