Liebert DM Series User manual

User Manual
Liebert®DM Series Air Conditioner
Precision Cooling
For Business-Critical Continuity™

New Liebert_DM Series Air Conditioner
User Manual
Version
V1.0
Revision date
April 28, 2013
BOM
31012860
Emerson Network Power provides customers with technical support. Users may contact
the nearest Emerson local sales office or service center.
Copyright © 2013 by Emerson Network Power Co., Ltd.
All rights reserved. The contents in this document are subject to change without notice.
Emerson Network Power Co., Ltd.
Address: No.1 Kefa Rd., Science & Industry Park, Nanshan District 518057, Shenzhen
China
Homepage: www.emersonnetworkpower.com.cn
E-mail: [e-mail]

Contents
Chapter 1 Overview ............................................................................................................................................................1
1.1 Model Description.................................................................................................................................................1
1.2 Product Introduction..............................................................................................................................................1
1.3 Basic Performance Parameters............................................................................................................................1
1.4 Main Components.................................................................................................................................................2
1.4.1 Indoor Unit.................................................................................................................................................2
1.4.2 Outdoor Unit..............................................................................................................................................2
1.5 Options .................................................................................................................................................................3
1.5.1 Humidifier ..................................................................................................................................................3
1.5.2 Heater........................................................................................................................................................3
1.5.3 Remote Monitor.........................................................................................................................................3
1.5.4 Energy-Saving Card..................................................................................................................................3
1.5.5 Power SPD................................................................................................................................................3
1.6 Ambient Requirements .........................................................................................................................................3
1.6.1 Operation Environment..............................................................................................................................3
1.6.2 Storage Environment.................................................................................................................................4
1.7 Refrigerant Charging Requirement.......................................................................................................................4
Chapter 2 Mechanical Installation.......................................................................................................................................5
2.1 Unpacking And Inspection....................................................................................................................................5
2.2 Installation Notes ..................................................................................................................................................5
2.3 System Installation Arrangement..........................................................................................................................5
2.3.1 General Arrangement................................................................................................................................5
2.3.2 System Installation Illustration...................................................................................................................6
2.3.3 Mechanical Parameters.............................................................................................................................7
2.4 Installing Indoor Unit.............................................................................................................................................8
2.4.1 Equipment Room Requirements................................................................................................................8
2.4.2 Installation Location Requirements............................................................................................................8
2.4.3 Installation Procedure................................................................................................................................9
2.5 Installing Outdoor Unit ........................................................................................................................................10
2.5.1 Installation Notes.....................................................................................................................................10
2.5.2 Installation Procedure..............................................................................................................................10
2.6 Piping for AC Unit ...............................................................................................................................................11
2.6.1 General Principles ...................................................................................................................................11
2.6.2 Installation Notes Of Connector...............................................................................................................12
2.6.3 Required Pipe Connections.....................................................................................................................12
2.6.4 Connecting Refrigerant Pipe....................................................................................................................12
2.6.5 Connecting Drain Pipe Of Indoor Unit .....................................................................................................14

2.6.6 Connecting Humidifier Water Supply Pipe (If Applicable)........................................................................14
2.7 Removing Transportation Fastener And Vibration Absorber...............................................................................15
2.8 Adding Refrigerant For Long Pipe System..........................................................................................................15
2.9 Check List...........................................................................................................................................................16
Chapter 3 Electrical Installation.........................................................................................................................................17
3.1 Task Introduction ................................................................................................................................................17
3.2 Notes ..................................................................................................................................................................17
3.3 Connecting Power Cable Of Indoor Unit.............................................................................................................17
3.4 Connecting Power Cable Of Outdoor Unit..........................................................................................................19
3.5 Connecting Control Cable...................................................................................................................................19
3.5.1 Connecting Control Terminals.................................................................................................................19
3.5.2 Connecting Monitoring Port Cable...........................................................................................................21
3.6 Connecting Energy-Saving Card.........................................................................................................................21
3.7 Check list............................................................................................................................................................23
Chapter 4 System Testing.................................................................................................................................................24
4.1 Start-Up Inspection.............................................................................................................................................24
4.2 Function Testing .................................................................................................................................................24
4.2.1 Cooling ....................................................................................................................................................24
4.2.2 Heating....................................................................................................................................................24
4.2.3 Humidifying..............................................................................................................................................25
4.2.4 Dehumidifying..........................................................................................................................................25
4.2.5 Checking Refrigerant Charge Capacity Of Lee-Temp Outdoor Unit........................................................25
Chapter 5 Micro-Processing Controller.............................................................................................................................26
5.1 Feature ...............................................................................................................................................................26
5.2 Appearance ........................................................................................................................................................26
5.3 LCD Screen........................................................................................................................................................26
5.4 Control Buttons...................................................................................................................................................27
5.4.1 Function Description................................................................................................................................27
5.4.2 Operation Example..................................................................................................................................27
5.5 Control Screen....................................................................................................................................................28
5.5.1 ON Screen...............................................................................................................................................28
5.5.2 Normal Screen.........................................................................................................................................28
5.5.3 Password Screen ....................................................................................................................................28
5.6 Menu Structure...................................................................................................................................................29
5.6.1 Main Menu...............................................................................................................................................29
5.6.2 Alarm Menu.............................................................................................................................................29
5.6.3 Set Points................................................................................................................................................31
5.6.4 System Status .........................................................................................................................................31
5.6.5 System Menu...........................................................................................................................................32
5.6.6 Help Menu...............................................................................................................................................34

5.6.7 Display Set ..............................................................................................................................................34
Chapter 6 System Maintenance........................................................................................................................................35
6.1 Electric Inspection...............................................................................................................................................35
6.2 Indoor Unit Maintenance.....................................................................................................................................35
6.2.1 Filter.........................................................................................................................................................35
6.2.2 Fan..........................................................................................................................................................36
6.2.3 Drain Pipe................................................................................................................................................37
6.2.4 Heater......................................................................................................................................................37
6.2.5 Humidifier ................................................................................................................................................37
6.2.6 Power SPD..............................................................................................................................................39
6.2.7 Thermal Expansion Valve........................................................................................................................39
6.2.8 High-Pressure Switch And Low-Pressure Switch....................................................................................40
6.2.9 Compressor.............................................................................................................................................40
6.3 Outdoor Unit Maintenance..................................................................................................................................41
6.3.1 Refrigeration System...............................................................................................................................41
6.3.2 Air-Cooled Condenser.............................................................................................................................41
6.3.3 Low-Temperature Unit Of Lee-Temp Outdoor Unit..................................................................................41
6.4 Maintenance Inspection Checklist.......................................................................................................................42
Chapter 7 Troubleshooting................................................................................................................................................43
Appendix 1 Menu Structure...............................................................................................................................................44
Appendix 2 Parameter Setting Table ................................................................................................................................45
Appendix 3 RDU-Cooling Air-Conditioner Single-Unit Manager Software Introduction.....................................................47

Chapter 1 Overview 1
New Liebert_DM Series Air Conditioner User Manual
Chapter 1 Overview
This chapter introduces the model description, product introduction, basic performance parameters, main
components, options and ambient requirement, and refrigerant charging requirement of the new Liebert_DM series
air conditioner (Liebert_DMAC for short).
1.1 Model Description
The model description of the Liebert_DMAC is shown in Figure 1-1.
Client code
1DM E07 M T 1: Standard; 2: High efficiency
Input power supply. M: 380V-3-ph-50Hz
Cooling capacity. 07: 7.5kW; 12: 12.5kW
Liebert_DM series air conditioner
E: indoor unit; C: outdoor unit; L: Lee-Temp outdoor unit
C
C: cooling only; O: with heater; H: with heater and humidifier
Figure 1-1 Model description
1.2 Product Introduction
The Liebert_DMAC is a small precise environment control system, specially designed for cooling the electrical
devices. It is applicable to environment control in equipment room and computer room. Featuring high reliability, it can
maintain a favorable running environment for precise devices such as sensitive devices, industry process devices,
communication devices and computers.
The cooling kit is provided as standard and it can precisely control the ambient temperature. The heater and
humidifier are provided as options and they can precisely control the ambient humidity. If the AC unit is only used for
cooling, the options are not needed.
The Liebert_DMAC provides a micro-processing controller that can automatically switch over to the required function
(cooling or heating, dehumidifying or humidifying), based on the programmed setpoints and room ambient conditions.
Each Liebert_DMAC consists of an indoor unit and an outdoor unit. Both units are installed on the floor separately.
Indoor unit
The Liebert_DMAC includes units with a cooling capacity of 7.5kW and 12.5kW, which are applicable to power
supply of 380V, 3-ph. You can select them according to the actual equipment room conditions.
Outdoor unit
The outdoor unit adopts air cooled mode. It is classified into two models: standard model and Lee-Temp model. The
Lee-Temp model can be used at lower temperature (see Table 1-1) than the standard model.
1.3 Basic Performance Parameters
The basic performance parameters of the Liebert_DMAC are given in Table 1-1.
Table 1-1 Basic performance parameters
Model
Nominal refrigeration
capacity (kW) Power（kW）
Energy efficiency
rate
Heating capacity[1]
(kW)
Humidification
capacity[2] (kg/h)
DME07M**1
7.5
2.5
3.0
3.2
2.5
DME12M**1
12.5
4.15
3.0
3.2
2.5
DME07M**2
7.5
2.34
3.2
3.2
2.5
DME12M**2
12.5
3.9
3.2
3.2
2.5

2Chapter 1 Overview
New Liebert_DM Series Air Conditioner User Manual
Model
Nominal refrigeration
capacity (kW) Power（kW）
Energy efficiency
rate
Heating capacity[1]
(kW)
Humidification
capacity[2] (kg/h)
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
1.4 Main Components
1.4.1 Indoor Unit
The indoor unit consists of evaporator, compressor, fan, micro-processing controller, thermal expansion valve,
strainer, filter, heater (optional), humidifier (optional) and surge protective devices (SPD, optional). For option
introduction, refer to 1.5Options.
Evaporator
Adopt a fin-tube heat exchanger with high efficiency. The distributor is designed and verified according to individual
model to ensure that the refrigerant is distributed evenly in each loop, improving the efficiency of the heat exchanger
to a great extent.
Compressor
Adopt a compressor with high efficiency ratio. It features low vibration, low noise and high reliability.
Fan
Adopt a centrifugal fan with high efficiency and high reliability. It features large airflow, long blowing distance, direct
driving and easy maintenance.
Micro-processing controller
Provide 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 diagnose system can automatically display current
fault information to facilitate equipment maintenance by maintenance personnel.
Thermal expansion valve
Adopt a thermal expansion valve with external equalizer type. It collects temperature and pressure signals at the
same time to accurately regulate the refrigerant flow.
Strainer
Filtrate the impurities generated during long-term system operation and ensure normal system operation.
Filter
Adopt nylon filter material with big mesh for Liebert_DMAC. The filter features compact structure and easy
maintenance. It can be washed repeatedly.
1.4.2 Outdoor Unit
The outdoor unit consists of fan and condenser. Other than the above components, the Lee-Temp model also
includes a low-temperature unit.
Fan
Adopt axial flow blades with low 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.
Condenser
Adopt a fin-tube heat exchanger with high heat dissipation and wavy fins. It is free of dust accumulation, and can be
easily cleaned and maintained.

Chapter 1 Overview 3
New Liebert_DM Series Air Conditioner User Manual
Low-temperature unit
Make the AC unit operate in cooling mode normally at the lowest outdoor temperature of -34°C.
1.5 Options
1.5.1 Humidifier
The humidifier can add pure water vapor (up to 2.5 kg/hour) into the room to control the indoor humidity within ranges
required by devices and computer.
The humidifier consists of a steam canister with automatic flushing control function, inlet tube, drain tube, solenoid
valve and steam distributor.
Note
1. The electrode humidifier should be installed and tested in factory.
2. The Liebert_DM AC can control the ambient humidity only after a humidifier is installed.
1.5.2 Heater
A ceramic heater with positive temperature coefficient can be selected. It is safe and reliable. When the surface
temperature is too high, it will reduce the heating power to avoid danger caused by over-temperature.A temperature
switch is provided on the surface of the heater, and it will cut off the power of the heater when the surface
temperature is too high. When the surface temperature decreases to normal, the temperature switch will restore the
operation of the heater automatically.
1.5.3 Remote Monitor
The Liebert_DMAC communicates with the host computer through a configured RS485 port and receives the control
of the host software. You can also select and configure a monitoring card to realize different monitoring functions. For
the descriptions of the host monitoring software RDU-Cooling developed by Emerson, refer to
Appendix 3 RDU-Cooling Air-Conditioner Single-Unit Manager Software Introduction.
1.5.4 Energy-Saving Card
The Liebert_DMAC 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 anAC
unit. When the temperatures measured by all energy-saving cards are lower than the setpoint in ‘Sleep Mod’ and only
indoor fan is running, if the ‘Sleep Mod’ is set to ‘ENAB’, theAC unit will turn off the indoor fan and enter the sleep
mode for saving the energy.
1.5.5 Power SPD
The power SPD is used for second level (C level) lightning over-voltage protection of the AC power. It can be
maintained easily and provides status indicating and alarm function.
Note
The humidifier, heater and power SPD should be installed in factory.
1.6 Ambient Requirements
1.6.1 Operation Environment
The operation environment requirements are listed in Table 1-2.

4Chapter 1 Overview
New Liebert_DM Series Air Conditioner User Manual
Table 1-2 Operation environment requirements
Item
Requirements
Installation position
The maximum equivalent horizontal distance between the indoor unit and outdoor unit[1]: 50m;
Vertical distance ΔH[2]: -5m ≤ΔH ≤20m
Installation mode
Indoor unit: vertical mode, mounting base ≥150mm;
outdoor unit: horizontal airflow mode
Ambient temperature
Indoor: 0°C ~ 40°C
Outdoor: standard model, -15°C ~ +45°C; Lee-Temp model, -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 error is 3%
Note:
[1]: For the equivalent lengths of parts, refer to Table 2-4.
[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
1.6.2 Storage Environment
The storage environment requirements are listed in Table 1-3.
Table 1-3 Storage environment requirements
Item
Requirements
Storage environment
Indoor, clean (without dust)
Ambient humidity
5%RH ~ 85%RH
Ambient temperature
-40°C ~ +70°C
Storage time
The total shipment and storage time should not exceed six months. Otherwise, the
performance needs to be re-calibrated
1.7 Refrigerant Charging Requirement
The low quality or counterfeit refrigerant will damage the system severely. Please use the refrigerant approved by
Emerson Network Power Co., Ltd. For the system abnormity or damage caused by using other brands of refrigerant,
the warranty will be invalid.
See Table 1-4 for the refrigerant brands approved by Emerson Network Power Co., Ltd.
Table 1-4 Approved refrigerant brands
Brand
LOGO
Note
DU PONT
The DU PONT refrigerant adopts
Emerson custom-made package
JUHUA

Chapter 2 Mechanical Installation 5
New Liebert_DM Series Air Conditioner User Manual
Chapter 2 Mechanical Installation
This chapter expounds the mechanical installation of the Liebert_DMAC, including unpacking & inspection,
installation notes, system installation arrangement, installing indoor unit, installing outdoor unit, piping, removing
transportation fastener and vibration absorber, adding refrigerant for long pipe system and check list.
2.1 Unpacking And Inspection
Move the product to the place most close to the final installation site and then unpack it.
If any part is found missing or damaged, please report to your carrier immediately. If any covert defect is found,
please report to the carrier and the local sales office too. Do not accept a damaged unit.
2.2 Installation Notes
1. The Liebert_DMAC adopts split-floor installation. The indoor unit must be installed on the floor in the equipment
room or computer room. The outdoor unit can be installed outdoors or on the floor in other rooms.
2. Before installation, make sure that the installation environment meets the requirements (see 1.6Ambient
Requirements) and that the building should be transformed to accommodate the construction work such as piping,
wiring and ventilation ducts.
3. The installers must strictly follow the design drawings for installation and reserve space for installation and
maintenance. The manufacturer’s engineering dimension drawings can serve as a reference.
2.3 System Installation Arrangement
2.3.1 General Arrangement
The system general arrangement diagram is shown in Figure 2-1. The standard pipe sizes are shown in Table 2-1.
Figure 2-1 General arrangement diagram

6Chapter 2 Mechanical Installation
New Liebert_DM Series Air Conditioner User Manual
Note
1. : Factory piping.
2. : Field piping (by technicians).
3. *: Check valve and traps are optional and not supplied by Emerson. But they are recommended for normal system operation
and easy maintenance. They should be installed on site by technicians.
4. +: Solenoid valve is a part of extended piping kit.
Table 2-1 Standard pipe sizes
Actual cooling capacity
Pipe length (m)
Discharge pipe OD
Liquid pipe OD
Liebert_DM series
7.5kW unit
5
1/2” (12mm)
3/8” (10mm)
12.5kW unit
5
5/8” (16mm)
1/2” (12mm)
2.3.2 System Installation Illustration
All equipment must be installed vertically. The Liebert_DMAC is available in two installation modes: outdoor unit
installed higher than indoor unit and indoor unit installed higher than outdoor unit. See Figure 2-2 for details.
Outdoor unit
Floor
Isolataion
floor
Max. 20m
1:200
7.5m
1:200
Insulation
material
Trap
Liquid pipe (not be exposed to sun)
Sealed
Protection
tube
Discharge pipe (slope)
Indoor unit
Condensation water
drain pipe (to outdoor)
Humidifier canister water
supply pipe (to water tap)
Outdoor unit above indoor unit
Min. 5m
1:200
Outdoor unit
Indoor unit
Sealed
Protection tube
Isolation floor
Discharge pipe (slope)
1:200
Condensation water
drain pipe (to outdoor)
Floor
Insulation
material
Liquid pipe (not be
exposed to sun)
Humidifier canister water
supply pipe (to water tap)
Indoor unit above outdoor unit
Figure 2-2 Installation illustration

Chapter 2 Mechanical Installation 7
New Liebert_DM Series Air Conditioner User Manual
2.3.3 Mechanical Parameters
Indoor unit
The mechanical parameters of the indoor unit are shown in Figure 2-3 and Table 2-2.
510 385
1750
510 510
600
500
1850
600
600
DME07kW DME12kW
Figure 2-3 Dimensions of indoor unit (unit: mm)
The shadows in Figure 2-3 indicate a reasonable installation and service space. The two sides of the unit need air
inlet. Enough service space must be reserved for the unit to facilitate maintenance.
The AC unit equipped with a heater should be kept a distance of minimum 150mm from combustible substance.
When testing the AC unit, keep the external static pressure below 150Pa lest the air volume becomes too low and the
heater becomes too hot.
Outdoor unit
The mechanical parameters of the outdoor unit are shown in Figure 2-4, Figure 2-5 and Table 2-2.
352
787
829
1240
352
787
Figure 2-4 Dimensions of standard outdoor unit (unit: mm)

8Chapter 2 Mechanical Installation
New Liebert_DM Series Air Conditioner User Manual
352
1037
575 1238
352
1037
575
829
Figure 2-5 Dimensions of Lee-Temp outdoor unit (unit: mm)
Table 2-2 Mechanical parameters of indoor unit and outdoor unit
Model
Cooling capacity (kW)
Dimensions (W × D × H, mm)
Net weight (kg)
Indoor unit
7.5
510 × 385 × 1750
90
12.5
600 × 500 × 1850
145
Outdoor unit Standard model
7.5
787 × 352 × 829
40
12.5
787 × 352 × 1240
60
Lee-Temp model
7.5
1037 × 352 × 829
53
12.5
1037 × 352 × 1238
95
2.4 Installing Indoor Unit
2.4.1 Equipment Room Requirements
The equipment room requirements are given as follows:
1. The equipment room should be well insulated and have a sealed damp-proof layer.
Note
The most important elements for maintaining normal environmental control in the conditioned room are damp proof and heat
preservation.
2. The outdoor air should be kept from entering to a minimum. The outside air will add the loads of heating, cooling,
humidifying and dehumidifying of the system. It is recommended that the inhalation of outside air be kept below 5% of
the total indoor airflow.
3. All the doors and windows should be properly sealed to minimize the leakage and the seams should be as narrow
as possible.
2.4.2 Installation Location Requirements
Note
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.
The installation location requirements are given as follows:
1. Try to locate the indoor unit in a capacious floor space to ensure its normal operation.
2. Avoid locating the indoor unit in confined areas that affect the airflow pattern, shorten cooling cycles and result in
down-draft and air noise.
3. Avoid locating the indoor unit in an alcove or at the extreme end of a long, narrow room.

Chapter 2 Mechanical Installation 9
New Liebert_DM Series Air Conditioner User Manual
4. Avoid locating multiple indoor units close to each other. This can result in crossing air patterns, uneven loads and
competing operation.
5. Do not install additional devices (such as smoke detectors) over the cabinet for facilitating routine maintenance.
Figure 2-6 indicates the installation location of the indoor unit.
Not recommended location
location
Recommended
Figure 2-6 Installation location of the indoor unit
2.4.3 Installation Procedure
1. Secure the mounting base made by yourself on the selected location. The outline and dimensions of the mounting
base are shown in Figure 2-7.
510
385
Rubber cushion
(8mm ~ 10mm thickness)
Steel plate (60 60 4)
H > 150
Rubber cushion
(8mm thickness) Angle iron (30 30 3) or
square tube (25 25 3)
×
×
×
×
×
×
Mounting base of DME07kW indoor unit
600
500
H > 150
Installation hole for
expansion bolt (M6 50)
Rubber cushion
(8mm ~ 10mm thickness)
Steel plate (60 60 4)
Rubber cushion
(8mm thickness) Angle iron (30 30 3) or
square tube (25 25 2)
×
×
×
×
×
×
×
Mounting base of DME12kW indoor unit
Figure 2-7 Mounting base (unit: mm)
2. Lay a rubber cushion with 8mm ~ 10mm thickness on the mounting base, as shown in Figure 2-7.
3. Place the indoor unit onto the mounting base and secure it.
4. Rotate the grilles to regulate the airflow direction of the indoor unit, and the regulating angle is 45°, as shown in
Figure 2-8.

10 Chapter 2 Mechanical Installation
New Liebert_DM Series Air Conditioner User Manual
Grill
The grilles can be rotated
following the arrow direction
Figure 2-8 Regulating airflow direction
2.5 Installing Outdoor Unit
2.5.1 Installation Notes
1. Install the outdoor unit in a place which is secure and easy for maintenance. Do not install it on ground-level sites
with public access and be away from residential areas.
2. Do not locate it directly in the environment that requires low noise.
3. To ensure heat dissipation effect, locate it in a clean area, which is away from loose dirt and foreign matter to avoid
clogging the heat exchanger.
4. Do not locate it in the vicinity of steam, hot air and exhausts.
5. Keep a clearance of more than 450mm between the outdoor unit and the wall, obstruct and adjacent devices.
6. Avoid areas where snow will accumulate at air-inlet side and air-outlet side of the outdoor unit.
7. Prepare a solid base capable of supporting the outdoor unit weight (see Table 2-2). The base should be at least
50mm higher than the surrounding ground and 50mm larger than the dimensions of the outdoor unit base, as shown
in Figure 2-11.
2.5.2 Installation Procedure
1. Place the outdoor unit on the base.
2. Secure the outdoor unit onto the base with expansion bolts. The installation hole sizes of the base are shown in
Figure 2-9 and Figure 2-10.
787
374
680 R6
394
Figure 2-9 Installation hole dimensions of standard outdoor unit base (top view, unit: mm)

Chapter 2 Mechanical Installation 11
New Liebert_DM Series Air Conditioner User Manual
680 1037
374
394
R6
Figure 2-10 Installation hole dimensions of Lee-Temp outdoor unit base (top view, unit: mm)
If multiple outdoor units need to be installed with one above the other, see Figure 2-11 to install them.
Bracket
4m 0.5m
50mm
50mm
Min. 50mm
Outdoor unit base
Base
Airflow
Airflow
Out-
door
unit
Out-
door
unit
Note:
1. Use 5# angle iron for bracket, when
two units are installed with one above
the other.
2. Use 6.5# channel steel for bracket, when
three units are installed with one above the
other.
Figure 2-11 Installing multiple outdoor units with one above the other
2.6 Piping for AC Unit
2.6.1 General Principles
1. Use copper pipes with quick thread connector to connect the indoor unit and the outdoor unit. If the pipe length
exceeds the standard pipe length (see Table 2-1) and straight copper pipe is used, piping joints must be brazed.
2. Follow standard industry procedures in selection and placement of pipe, system evacuation and charging with
refrigerant (only when pipeline is too long). The standard refrigerant of the AC unit is R22.
3. Give considerations to pipeline pressure drop, oil return to the compressor, to avoid oil leakage and clogging in
parts of the system and minimize noise and vibration to the greatest extend.
4. Consult Emerson before installation on whether measures such as using extended piping kit are needed, if the
equivalent length exceeds 50m, or if the vertical distance between the indoor unit and the outdoor unit exceeds the
values in Table 2-3.
Table 2-3 Vertical distance between indoor unit and outdoor unit
Relative position
Value
Outdoor unit installed higher than indoor unit
Maximum: 20m
Outdoor unit installed lower than indoor unit
Maximum: 5m

12 Chapter 2 Mechanical Installation
New Liebert_DM Series Air Conditioner User Manual
5. The equivalent length of each part is given in Table 2-4. The resistance loss caused by elbows and valves has
been taken into consideration.The installer should confirm if these values are appropriate for site conditions.
Table 2-4 Equivalent length of each part
Liquid pipe OD (inch)
Equivalent length (m)
90° elbow
45° elbow
T-type three way
3/8
0.21
0.10
0.76
1/2
0.24
0.12
0.76
5/8
0.27
0.15
0.76
3/4
0.3
0.18
0.76
7/8
0.44
0.24
1.1
1-1/8
0.56
0.3
1.4
2.6.2 Installation Notes Of Connector
Be careful when connecting the quick thread connector. Read through the following steps before making connection.
1. Remove the dust-proof caps.
2. Carefully wipe coupling seats and threaded surface with a clean cloth.
3. Lubricate the male thread with refrigerant oil.
4. Thread the coupling halves together by hand to ensure that the threads mate properly.
5. Tighten the coupling body’s hexagon nut and union valve until a definite resistance is felt.
6. Use a marking pen to draw a line lengthwise from the coupling union nut to the bulkhead. Tighten the nuts an
additional quarter turn with two wrenches. The misalignment of the lines shows how much the coupling has been
tightened. The final quarter turn is necessary to ensure that the joint does not leak. Two wrenches must be used to
cooperate with each other during connection, because one wrench can damage the coupling copper lines easily.
The recommended torque values are listed in Table 2-5.
Table 2-5 Recommended torque value
Coupling size Torque value (N
.
m)
5/8”
7 ~ 8
3/4”, 7/8”
25 ~ 32
2.6.3 Required Pipe Connections
Refer to Figure 2-2, the required pipe connections are as follows:
Refrigerant pipe between the indoor unit and the outdoor unit (discharge pipe and liquid pipe).
Drain pipe of the indoor unit.
The following pipe connection is required if a humidifier is selected.
Water supply pipe to the humidifier.
Note
Before starting-up, ensure that all pipe connections have been completed without leakage after engineering installation.
2.6.4 Connecting Refrigerant Pipe
Piping notes
1. The copper pipes provided by the factory are 5m (see Table 2-1). If longer pipes are required, contact Emerson or
your sale agency.
2. The liquid pipe is the refrigerant liquid pipe of the outdoor unit outlet. So a reasonable pipe diameter and length
should be selected for the liquid pipe to ensure that the pressure drop of the refrigerant liquid through the pipe during
unit operation does not exceed 40kPa (5psi ~ 6psi).
3. The pipe should be installed and removed with care so that they will not get kinked or damaged. Use tube benders
and make all bends before making connections to either end.

Chapter 2 Mechanical Installation 13
New Liebert_DM Series Air Conditioner User Manual
4. If jointing mode is needed, all refrigerant piping should be connected with silver-brazed joints.
5. Check piping supports, leakage testing, dehydration of refrigerant pipes and evacuation before using. Use vibration
isolating support to isolate the refrigeration pipes from the building.
6. Use a soft and flexible material to pack around the pipes to protect them from damage caused by going through
openings in walls and to reduce vibration transmission.
7. When installing the outdoor unit 7.5m higher than the indoor unit, a trap should be installed on the discharge pipe.
This trap will retain refrigerant oil in the off cycle of the compressor. When the compressor starts, oil in the trap will be
carried up the vertical riser and return to the compressor immediately.
Pipe connector position
The pipe connectors inside the indoor unit are shown in Figure 2-12.
Aamplified
A
Condensate water
drain pipe (I.D.19mm)
Discharge pipe:
straight pipe 1/2"-12mm;
connector 3/4"-20mm thread
Liquid pipe:
straight pipe 3/8"-10mm;
connector 5/8"-16mm thread
Knock-out hole
Pipe connectors inside DME07kW indoor unit
Bamplified
B
Condensate water
drain pipe (I.D.19mm)
Discharge pipe:
straight pipe 5/8"-16mm;
connector 7/8"-22mm thread
Liquid pipe:
straight pipe 1/2"-12mm;
connector 3/4"-20mm thread
Knock-out hole
Pipe connectors inside DME12kW indoor unit
Figure 2-12 Pipe connectors inside the indoor unit