Vertiv | Liebert PEX4 | User Manual
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Product Overview
1.4.10.
Dehumidification- EC Fan
For dehumidification, the Compressor operates a specific cycle which uses an Electronic Expansion Valve (EEV)
control logic called
T
e
. This EEV control logic adjusts EEV opening (normally closed) to reduce the surface
temperature of the coil below the return dew point condition.
1.4.11.
Remote Air-Cooled Condenser
Refer to “LSF/LDF condenser User Manual” and “LVC Series Condenser User Manual.”
1.4.12.
Water-Under-Floor Sensor
Each unit is supplied with single water under floor point detector as standard. The alarm is triggered when the
‘water-under-floor sensor alerts the controller upon detection of water.
1.4.13. Controller
The Controller provides a simple operational user-interface and it is developed by using the latest and highly
advanced PID regulation technology. The controller features self-recovery power failure and protection against
high/low voltage. An accurate running status of the major components can be viewed through the menu
operation. It uses RS485 to configure Modbus protocol or SIC card (optional) to configure SNMP protocol.
1.4.14. Color Display and HMI Features
PEX4 is equipped with 9-inch color display, which enables monitoring of operating status of the precision AC
through menu-driven operations. It features auto restart function with high and low voltage protection, phase
loss protection, and phase reversal protection. It can display up to 500 historical alarms.
It also has HMI features such as Temperature control– Proportional, PI, PID, Position Increment; different
scenario for Room cooling or Optimizing aisle cooling. The cooling capacity is controlled via sensors such as
return air temperature/ supply air temperature/ remote rack temperature sensors, etc. The Inverter compressor
capacity helps in modulation for variable speed. The HMI also facilitates Supply and Return Air control, Heating
control, EEV control, EC fan control, Humidification control, and Static Air Pressure control.
1.4.15. Monitoring
Liebert PEX4 inverter air conditioner series is capable of connecting to the Building Management System/
Building Automation System using the following protocols:
•
Modbus RTU – Modbus Remote Terminal Unit (RTU) communication protocol over a RS-485 serial network
(also known as Modbus RTU RS-485)
•
SNMP (need to choose SIC card which is an optional component)
