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Vertiv Co. Ltd.
Notice
The purchased products, services, and features are stipulated by the contract made between
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document may not be within the purchasing scope or the usage scope. Unless otherwise
specified in the contract, all statements, information, and recommendations in this document are
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• China
Website: www.vertivco.com.
E-mail:
Customer service hotline:
• Asia Pacific
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Vertiv | Liebert DM Series Precision Air Conditioner | User Manual
Purpose of the Document
Situation
Description
The Warning/Danger/Caution note
degradation, or interruption in service.
The Note section indicates additional and
This document applies to the Liebert DM series of precision air conditioners and cooling solutions
which maintain an optimal environmental control mainly for testing laboratories, data center rooms
and similar technological ecosystems at minimal operating costs.
This document explains the product description, installation measures, operational workflow,
maintenance, and detailed aspects from the user perspective. The figures used in this document
are for reference only.
Please read this manual carefully before installing, maintaining, and troubleshooting, especially
the warning information in the manual
Styling used in this Guide
The styles used in the manual will be defined as mentioned in the following table:
indicates a hazardous or potentially
Warning/Danger/Caution
harmful situation that can result in death
or injury. It also indicates instructions that
need to be adhered to, failing which may
result in danger and safety issues thereby
having an adverse effect on the reliability
of the device and security. Even for
practices not related to physical injury, the
content under the Warning heading is
used for precautions which need to be
taken which, otherwise, could result in
equipment damage, performance
Note
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual
useful information including tips and
tweaks. It also calls attention to best
practices and industry-best protocols that
are standardized and help make maximum
utilization of the resources at hand.
Helpful information related to the
mainstream stuff also comes under the
Note heading helping the users get to
grips with the definitions, concepts, and
terminologies used in the manual.
Version History
Issue
Revision
Changes
1
1.0
-------
afety Precautions and Measures
S
The important safety precautions and measures that should be followed during the installation and
maintenance of the Liebert DM models are described in the following sections.
Read the manual prior to installation and operation of the unit. Only qualified personnel should
move, install, or service this equipment.
The user reads and takes into account all the precautions, compliance, and safety measures before
working on the equipment. The unit control must be used exclusively for the purpose which it is
intended for; the manufacturer takes no liability for incorrect use or a modification to the unit
control.
Adhere to all the Warnings and Cautionary measures included in the manual.
Please read this manual carefully before installing, maintaining and troubleshooting; especially the
Warning/ Danger/ Caution information in the User Guide. Apart from the User Guide, also pay
attention to the warning labels on the unit and its components.
This manual is retained for the entire service life of the machine. The user must read all the
precautions, danger, warnings, and cautionary measures mentioned in the manual prior to
carrying out any operations on the machine. Each machine is equipped with an electric
insulation which allows the users to work in safe conditions. The main switch is positioned on
the electrical panel cover; Open the right door to access it. Before any maintenance operation,
switch off the machine with this electronic insulation device in order to eliminate risks such as
electrical shocks, burns, automatic restarting, moving parts, and remote control. The panel key,
supplied along with the unit, must be kept by the personnel responsible for the maintenance.
The protective covers can be removed after the electric power has been cut off by opening
the main switch.
In the following section, take a look at the various cautionary measures and warnings that need to be read
carefully prior to installing or operating the system.
Disconnect the local and remote power supplies prior to working with the unit.
Prior to the installation process, read all the instructions, verify if all the parts are in place, and check the
nameplate to ensure that the voltage matches the utility power that is available for that unit.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual
The controller doesn’t isolate power from the unit even in the Off mode. Moreover, some internal
components require and receive power even during the Off mode.
If the unit door is open while the fans are operating, the airflow may result in abrupt slamming of the door
resulting in injury. Another aspect is the presence of small objects in the fans bay which may result in object
ejection during the fan start-up and there is a probable risk of being hit by these objects leading to grievous
injury as well as causing equipment damage.
The unit contains fluids and gasses under high pressure. Therefore, the pressure should be relieved
before working with the piping.
Various components such as compressors, refrigerant discharge lines, and humidifiers are extremely hot
during the unit operation. Therefore, allow sufficient time for the unit to cool down before working with the
unit cabinet. Handle the unit with extreme caution and wear safety equipment such as protective gloves,
safety shoes, and arm protection while working with the hot compressors, discharge lines, and reheats.
There is a risk of leaking water that can cause damage to the equipment as well as the building. There
should be an effective water drain connection and facilities. Installation should be precise. Implementation
of the application and service practices should be suitable and fault-free. Not complying with these norms
will result in water leakage from the unit. Water leakage can result in massive damage and loss of critical
equipment in the hosting ecosystem. Therefore, care should be taken to ensure that the unit must not be
located directly above any equipment that could sustain damage due to water and excessive moisture.
Using a leak detection system for unit and system supply lines are recommended by Vertiv Co.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual
1.1 Model Nomenclature....................................................................................................................................................... 3
1.4.1 Electric Heater ............................................................................................................................................. 10
1.4.4 Power SPD..........................................................................................................................................................11
1.5 Working Conditions................................................................................................................................... 11
2.3.4 Outdoor unit ................................................................................................................................................... 25
2.3.5 Indoor Unit Installation ........................................................................................................................... 26
2.3.6 Outdoor Unit Installation ...................................................................................................................... 27
2.3.8 Piping for AC Unit ...................................................................................................................................... 29
2.3.9 Installation Notes Of Connector ..................................................................................................... 30
2.3.15 Connecting Drain Pipe Of Indoor Unit ...................................................................................... 35
2.3.16 Connecting Humidifier Water Supply Pipe (If Applicable) ........................................ 35
2.3.17 Removing Transportation Fastener And Vibration Absorber ................................. 35
2.3.18 Adding Refrigerant For Long Pipe System ........................................................................... 36
2.3.19 Check List ...................................................................................................................................................... 37
3 System Operation ......................................................................................................................................................................... 51
3.2.1 Features ............................................................................................................................................................. 52
3.2.4 Control Buttons ........................................................................................................................................... 53
3.2.5 Control Buttons Operation Example ............................................................................................ 54
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual
3.2.6 ON Screen ........................................................................................................................................................ 55
3.2.7 Language Screen ........................................................................................................................................ 55
3.2.8 Normal Screen .............................................................................................................................................. 56
3.3 Function Testing ........................................................................................................................................................... 57
3.3.5 Checking Refrigerant Charge Capacity of Low-Temp Outdoor .............................. 58
3.4 Micro-Processing Controller Menu Options ............................................................................................. 59
3.4.1 Main Menu........................................................................................................................................................ 59
3.4.2 Alarm Menu ................................................................................................................................................... 60
3.4.3 Set Points ......................................................................................................................................................... 63
3.4.4 System Status............................................................................................................................................... 63
3.4.5 System Menu .................................................................................................................................................66
3.4.6 Help Menu ....................................................................................................................................................... 67
3.4.7 Display Set .......................................................................................................................................................68
4 General Maintenance ................................................................................................................................................................69
4.1 Electric Inspection ........................................................................................................................................................ 70
4.2 Indoor Unit Maintenance ........................................................................................................................................ 70
4.2.2 Fan ......................................................................................................................................................................... 72
4.2.6 Power SPD ....................................................................................................................................................... 74
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual
PART I
GENERAL INFORMATION
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 1
1 Introduction
The Liebert DM series is the next generation series of small air conditioners that provide precise
environmental control. The Liebert DM models are the latest in the long line of modern enterprisegrade products from the Liebert family. Incorporating the high standards associated with the Liebert
name, the DM series utilizes the latest technology, system components, and a streamlined
manufacturing process.
Liebert DM air conditioners are products that are specifically created and designed for cooling the
electrical devices. It is applicable to equipment rooms, computer rooms, and similar ecosystems
which call for a high degree of accuracy and precision in maintaining the ambient temperature. It
addresses the needs and challenges associated with such applications and setups. It caters to
sensitive applications which need a suitable environment for optimal performance. Therefore, care
should be taken while testing these sensitive products or maintaining a favorable environment for
mission critical equipment, as even a slight deviation may lead to inaccurate results. Precision Air
Conditioning must not only keep room conditions within a specific range but also must have the
precision to react quickly to a drastic change in heat load and prevent wide temperature fluctuations.
The DM air cooled AC unit is packed with features such as high reliability, high sensible heat ratio,
and large airflow. The unit is an air-cooled single cooling system and configured with DC Speed
Regulation back- inclined centrifugal fan.
Packed with a host of features, it lowers the sound emissions significantly and thereby reduces the
noise pollution. It is a top-notch system that adheres to the standard in Precision Air Cooling in
terms of energy-efficiency, space requirements, and reliability.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 2
Figure 1-1 shows the appearance of various models in the Liebert DM series:
Figure 1-1
1.1 Model Nomenclature
The model nomenclature of the Liebert DM AC is shown in Figure 1-2:
Figure 1-1
1.2 Basic Performance Parameters
The basic performance parameters of the Liebert DM AC are given in Table within
Listing 1.1.
Listing 1.1
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 3
Model
Nominal
cooling
capacity
(kW)
Power
(kW)
Annual
energy
efficiency
ratio
Heating
capacity
[1]
(kW)
Humidification
capacity
[2]
(kg/h)
DME07M**5
6.85
2.36
2.9
3.2
1.5
DME12M**5
11.9
4.1
2.9
3.2
1.5
Note:
[1]: The heating capacity is only for the models with heating function;
[2]: The humidification capacity is only for the models with humidification function
1.3 Product Description
The Liebert DM AC unit is a comprehensive system that includes all the main functions fundamental to
precision cooling units such as cooling, humidification, dehumidification, re-heating, air filtration,
condensation management, temperature and humidity control, alarm functions and compatibility with
data communications. Liebert DM AC is designed to comply with mission-critical requirements and
ensure that servers are maintained at the correct temperature and humidity levels.
Figure 1-3 shows the various components and their respective locations:
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 4
Figure 1-2
Item
Description
Item
Description
1
Heater
2
Evaporator
3
Centrifugal Fan
4
Compressor
5
Infrared Humidifier
6
Microcontroller Display
7
Filter
Listing 1.2
In the following sections, take a look at the list of components used in the Liebert DM AC series.
1.3.1 Compressor
The Liebert DM AC series models comprise of a scroll compressor which has a host of promising
features such as low operating noise, less vibration and high reliability. Its compactness, smooth
compression with scroll operation and high energy efficiency ratio makes it an ideal compressor to
bank on for the DM series.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 5
Figure 1-3 shows the image of a compressor.
Figure 1-4
1.3.2 Evaporator
Heat exchanger design and appropriate air distributions are important factors that determine optimum
performance. The Evaporator used in the Liebert DM AC models consists of a fin-tube heat exchanger
for higher efficiency. The sophisticated design of the distributor ensures that the refrigerant is
distributed evenly in each loop, thereby improving the effectiveness of the heat exchanger.
Figure 1-5 shows the image of an Evaporator.
Figure 1-5
1.3.3 Thermal expansion valve (TXV)
The thermal expansion valve controls the amount of refrigerant flow into the evaporator thereby
controlling the superheat at the outlet of the evaporator. Liebert DM consists of a thermal expansion
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 6
valve with external equalizer type. It collects temperature and pressure signals at the same time to
accurately regulate the refrigerant flow.
Figure 1-5 depicts the image for the TXV:
Figure 1-6
1.3.4 Micro-processing Controller
The Controller adheres to the latest and highly advanced PID regulation technology. It provides a
simple operation user interface with multi-level password protection, self-recovery upon power failure,
high-voltage & low-voltage protection, phase loss protection, automatic phase-sequence switching
upon anti-phase and rotate speed control of the outdoor fan. The expert-level fault diagnoses system
can automatically display current fault information to facilitate equipment maintenance by
maintenance personnel.
Figure 1-7 depicts the panel of the Microcontroller:
Figure 1-7
1.3.5 Strainer
The Strainer filters the impurities generated during long-term system operation and ensures normal
system operation.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 7
1.3.6 Filter
Moisture can have an adverse effect on the operation and life of a system in the refrigeration cycle.
To counter that effect, Filter-driers are used to filter out particles, and remove and hold moisture to
prevent it from circulating through the system. The Liebert DM AC consists of nylon filter material
with big mesh. The filter features compact structure and easy maintenance. It can be washed
repeatedly.
1.3.7 Centrifugal Fan
Centrifugal fans are rigid and strong metal fans. Its axial flow blades help in reducing the noise. The
single-phase motor with high performance is customized based on the power grid of base stations, so
it can work over a wide voltage range with high reliability. It features large airflow, long blowing
distance, direct driving and easy maintenance.
Figure 1-8 depicts the image for the Centrifugal Fan:
Figure 1-8
1.3.8 Condenser
The Liebert range of air-cooled condensers offers many advantages, including sharp design, antirust
aluminum cabinets, low sound levels, and reliable operations over a wide range of ambient conditions.
Figure 1-9 depicts the image of a condenser:
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 8
Figure 1-9
1.3.9 Sight Glass
The sight glass is a utility for observing the refrigerant state; specifically the moisture content of the
system. If the moisture content exceeds the levels of defined standards the color changes, thereby,
indicating irregularity in the moisture content.
1.3.10 Infrared Humidifier
The infrared humidifier consists of infrared humidifier lamp, water injection valve, humidifying water
dish, temperature alarm protection devices and water level alarm device.
The infrared humidifier in the Liebert DM series provides quicker and more responsive operation
which is quite important for mission-critical applications. These humidifiers reduce the dependency of
water quality and simultaneously achieve full capacity in quick time using almost any water quality.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 9
Figure 1-10 depicts the image of a Humidifier.
Figure 1-10 Humidifier
1. The electrode humidifier should be installed and tested at the factory.
2. The Liebert DM AC can control the ambient humidity only after a humidifier is installed.
1.4 Optional Components
1.4.1 Electric Heater
T
he PTC electric heaters are used as they have lower running temperatures thereby ensuring
operational safety. PTC heaters are less susceptible to overheating and therefore, are long lasting
due to less wear. Lower maintenance and smooth functioning make it an important utility in Liebert DM
AC models.
Figure 1-11 shows an image of the Electric Heater:
igure 1-11
F
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 10
1.4.2 Remote Monitor
The Liebert DM AC communicates with the host computer through a configured RS485 port and
receives the control of the host software. Select and configure a monitoring card to realize different
monitoring functions. For the descriptions of the host monitoring software RDU-Cooling developed by
Vertiv Co., Refer to Appendix 4 RDU-Cooling Air-Conditioner Single-Unit Manager Software
Introduction.
1.4.3 Energy-Saving Card
The Liebert DM AC can monitor the maximum room temperature with the energy-saving card
located outside the unit cabinet. The card is placed in position with high heat load and temperature.
Up to four cards can be used for an AC unit. When the temperatures measured by all energy-saving
cards are lower than the set-point in ‘Sleep Mod’ and the only indoor fan is running; if the ‘Sleep Mod’
is set to ‘ENAB’, the AC unit will turn off the indoor fan and enter the sleep mode for saving the
energy.
1.4.4 Power SPD
T
he power SPD is used for the second level (C level) lightning over-voltage protection of the AC
power. It can be easily maintained and provides status indicating and alarm function.
1.5 Working Conditions
In
this section, take a look at the environmental conditions including the Operating and Storage
environment.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 11
1.5.1 Operating Environment
The table in Listing 1.3 defines the Operating environment parameters including the Ambient
Temperature, Protection level, Altitude, and Voltage range.
Listing 1.3
Item Requirements
The maximum equivalent horizontal distance between the
Outdoor: standard model, -15°C ~ +45°C; Low-Temp model, -
temperature
34°C ~ +45°C
Ambient humidity 30%RH ~ 80%RH
Protection level Outdoor unit: IPX4
Altitude < 1000m. Derating is required when the altitude exceeds 1000m
Operation voltage
range
380V (-15% ~ +15%), settable according to different
environments, the tolerance is 3%
Note: [1]: For the equivalent lengths of parts, refer to Listing 2.5
[2]: The value is positive if the outdoor unit is installed above the indoor unit; negative
if the indoor unit is installed above the outdoor unit
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 12
1.5.2 Storage Environment
Item
Requirement
Storage environment
Indoor, clean (without dust)
Ambient humidity
5%RH ~ 85%RH
Ambient temperature
-40°C ~ +70°C
Total transportation and storage time should not exceed
Brand
Logo
Note
The DU PONT refrigerant adapts
The following table defines the Storage Environment parameters including the ambient humidity,
ambient temperature, and storage time conditions.
Listing 1.4
Storage time
six months. Otherwise, the performance needs to be recalibrated
Another essential aspect is the quality and the make of the refrigerant oil. Adding poor quality oil,
counterfeit oil, or oil for a different model will damage the system. The quality issue due to the wrong
refrigerant oil will result in the voiding of warranty.
1.5.3 Refrigerant Charging Requirement
The low quality or counterfeit refrigerant will damage the system severely. Please use the refrigerant
approved by Vertiv Co., Ltd. For the system abnormality or damage caused by using other brands of
refrigerant, Refer the table in listing 1.5 for the refrigerant brands approved by Vertiv Co., Ltd.
Listing 1.5
DU PONT
custom made package
JUHUA
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 13
Part II
INSTALLATION
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 14
2 Installation
2.1 Pre-Installation
Pre-installation contains the following 3 sub-sections, namely –
Transportation and Movement
Unpacking
Inspection
2.1.1 Transportation and Movement
When transporting the system, Railroad is a preferable choice. However, if railroad transportation is
not possible, then the truck transport option is an optimal choice. One precaution is to choose roads
that do not have too many bumps and if any, avoid it as much as possible.
It is recommended that equipment like an electric forklift is utilized for these heavy duty systems.
Move the equipment to a location which is in the vicinity of the installation site.
If an electric forklift is used, insert the tines of the forklift below the pallet as displayed in Figure 2-1.
Align the tines with the center of gravity to prevent the equipment from falling over. Figure 2-1
depicts the way the tines of the forklift are inserted below the pallet and in the same image; the
graphic to the right indicates that the tines are aligned with the center of gravity to prevent the
equipment from falling over:
Figure 2-1
In the previous Figure 2-1, the air conditioner is lifted using the forklift truck and is aligned with the
center of gravity. While moving the indoor unit, the obliquity has to be maintained at an angle of 75°
to 105°.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 15
Figure 2-2 depicts the 75° to 105° obliquity that is suitable to move the air conditioning package to the
vicinity of the desired location:
Figure 2-2
2.1.2 Unpacking
The cabinet uses a honeycomb cardboard and winding stretch film for packaging purposes. Shift the
product to a location closer to the final installation site prior to unpacking the unit.
Initially, remove the top cover and winding stretch film. Next, remove the honeycomb cardboard as
depicted in Figure 2-3.
Figure 2-3
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 16
The unit is fixed on the packing pallet with M8*20 and M8*80 screws. Use a 17 mm open-end spanner,
ratchet spanner, or sleeve to remove the screws.
Figure 2-4 to shows the schematic diagram:
Figure 2-4
2.1.3 Inspection
Moving forward, check the system fittings and its components against the packing list to ensure that
everything is in place and the assembly is intact. If any parts or components are missing or damaged,
immediately report to the carrier about the same. If hidden damages are observed, then contact the
local offices of that carrier as well as Vertiv Co., at the earliest.
2.2 Installation Preparation (Site Preparation)
The Liebert DM AC series of air conditioners is streamlined for maintaining a favorable environment
for data centers, computer rooms, and similar ecosystems. Strict adherence to the installation
procedures is mandatory in order to ascertain proper installation of the air conditioner.
2.2.1 Equipment Room Requirement
The equipment room must be prepared to ensure a smooth operation flow and obtain accurate
results. The equipment room must meet the standards for appropriate ventilation and heating. The
design specifications for the air conditioners must be ideal and should match the energy-efficient
design standards.
Following are the requirements for maintaining a favorable room environment prior to installation:
The equipment room should be well insulated and have a sealed damp-proof layer.
The most important elements for maintaining normal environmental control in the conditioned room
are damp proof and heat preservation.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 17
The outside air will add to the loads of heating, cooling, humidifying and dehumidifying of the system. It is
recommended that the inhalation of outside air should be kept below 5% of the total indoor airflow.
All the doors and windows should be properly sealed to minimize the leakage and the seams should be as narrow
as possible.
Vertiv Co. recommends that the site preparation is defined as per the requirements. However, if these
requirements are not met, rectifications must be made on the site so that it complies with the specified
requirements and conditions. However, if the recommended rectifications or modifications are not
implemented, then Vertiv Co. does not guarantee the accuracy and precision of the temperature and
humidity provided by the Liebert DM model. One important aspect to be considered is that the indoor
unit must not be used for the outdoor environment.
2.2.2 Installation Space requirements
Air conditioners in the Liebert DM AC series are advanced precision air cooling units and therefore,
these air conditioners must be installed, preferably in a capacious floor space to ensure its normal
operation.
The Liebert DM AC can generate condensate water. Water leakage can cause damage to other precise
equipment nearby. Do not install the AC units in the vicinity of any precision equipment. The installation
site must provide drainpipes.
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 18
The installation location requirements are given as follows:
Not recommended location
location
Recommended
• Avoid locating the indoor unit in confined areas that affect the airflow pattern, shorten cooling cycles and
result in down-draft and air noise.
• Avoid locating the indoor unit in an alcove or at the extreme end of a long, narrow room.
• Avoid locating multiple indoor units close to each other. This can result in crossing air patterns, uneven
loads and compete for operation.
• Do not install additional devices (such as smoke detectors) over the cabinet for facilitating routine
maintenance.
The following Figure 2-5 depicts the installation location of the indoor unit.
Figure 2-5
Vertiv | Liebert DM Series Precision Air Conditioner | User Manual 19
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