Vertiv Liebert PEX+ Series

Questions and Answers

P
pamela19Aug 5, 2025
How to troubleshoot a Vertiv Liebert PEX EC fan that won't start?
- J
  Jonathan PierceAug 5, 2025
  If the Vertiv Air Conditioner's EC fan won't start, the issue might stem from a disconnected power supply. Start by verifying the MCB of the main fan. Then, check if the L1, L2, and L3 fan power lines are off, experiencing a phase failure, or suffering from undervoltage. Alternatively, a control panel failure could be the culprit. Check for a 24 Vac voltage between points P36-3 and E1; if absent, inspect the control panel. Also, check the green LED next to silicon control Q5 on the control panel to see if it's illuminated. Finally, a voltage issue might exist. Check if the voltage between P53-2 and P53-3 is less than 10 Vdc; if not, examine the control panel.
J
johnsonalbertAug 13, 2025
What to do if Vertiv Air Conditioner displays an air loss alarm?
- M
  Mathew MolinaAug 13, 2025
  If your Vertiv Air Conditioner is displaying an air loss alarm, it may be due to a clogged air filter restricting airflow. Inspect the filter and replace it if it's blocked.
M
millerjohnAug 21, 2025
Why is the humidification ineffective in my Vertiv Liebert PEX?
- T
  Thomas DavisAug 21, 2025
  If the humidification is ineffective in your Vertiv Air Conditioner, start by checking if the water supply is normal and if there is water in the water pan. Also, check whether the water supply solenoid valve is working and if the water supply pipe is not clogged. Finally, check the state of the high water-level switch and the water level regulator.
M
Monique ColemanAug 27, 2025
How to fix ineffective humidification in Vertiv Liebert PEX if the contactor does not close?
- M
  Matthew JohnsonAug 28, 2025
  If humidification is ineffective in your Vertiv Air Conditioner, and the humidification contactor isn't closing, examine the contactor and its circuit voltage. Also, check the opened safety devices of the infrared humidifier, specifically the Water pan over-temperature protection switch and lamp over-temperature protection switch.

Summary

Purpose of the Document

Styling used in this Guide

Explains the meaning of different styles used in the manual.

Version History

Details the version history of the user manual.

Product Overview

1.1. Product Introduction

Introduces the Liebert PEX+CW series of Precision Air Conditioners.

1.3. Model Nomenclature

Explains the 25-digit model nomenclature for PEX+CW series.

1.4. Components of PEX+CW Model

Provides an overview of the main components of the PEX+CW model.

1.6. Storage & Operating Environment Requirements

Details storage and operating environment requirements for the unit.

Installation

2.1. Pre-installation

Covers pre-installation steps including transportation and unpacking.

2.2. Installation Preparation (Site Preparation)

Details requirements for the equipment room and installation space.

2.3. Mechanical Installation

Provides information on mechanical installation procedures and dimensions.

2.5. Lowering the Fan

Describes the procedure for lowering the fan using the provided tool.

Electrical Installation

3.1. Installation Notes

Provides essential notes and precautions for electrical installation.

3.2. Cabling of Indoor Unit

Details the locating of electrical ports and cabling for the indoor unit.

3.3. Electrical Installation Checklist

A checklist to confirm the completion and correctness of electrical installation.

iCOM Controller Operation

4.2. Button and Indicator Panel

Describes the buttons and indicators on the iCOM controller panel.

4.4. Main Interface

Explains the main interface of the iCOM controller and its display modes.

4.5.2. Setpoints

Details how to browse and set various operational parameters (setpoints).

4.10. Teamwork Modes

Explains different teamwork modes for networked cooling units.

System Start-up Commissioning

6.1. Start-up Commissioning

Covers preparation and procedures for system start-up commissioning.

6.2. Commissioning Procedures

Details the step-by-step procedures for commissioning the unit.

System Operation and Maintenance

7.1. Routine Maintenance Inspection Items (Monthly)

Lists monthly inspection items to check system function and wear.

7.2. Routine Maintenance Inspection Items (Semi-Annual)

Lists semi-annual inspection items for system components.

7.5. Appearance Inspection and Maintenance of Controller Components

Covers visual inspection and maintenance of controller components.

7.6. Filter Maintenance Guide

Provides guidance on checking and replacing the unit's dust filter.

Diagnosis and Troubleshooting

8.1. Fault Diagnosis and Treatment of Fans

Guides on diagnosing and treating common faults related to the unit's fans.

8.2. Fault Diagnosis and Treatment of Infrared Humidifier

Guides on diagnosing and treating faults related to the infrared humidifier.

8.3. Refrigeration System - Fault Diagnosis and Treatment

Provides fault diagnosis and treatment for the refrigeration system.

Appendix I: Content of Harmful Substances in Products

Vertiv Liebert PEX+ Series Specifications

General

Refrigerant	R410A
Compressor Type	Scroll
Humidity Control	Optional
Control System	Liebert iCOM control
Airflow Configuration	Upflow, Downflow
Dimensions (HxWxD)	Varies by model
Weight	Varies by model
Communication	Modbus, SNMP