Midea MLSC380A-SB3Z User manual

DM16-03.01.46en
Applicable Model:
MLSC380A-SB3Z/MRH380A-B3Z
MLSC500A-SB3Z/MRH500A-B3Z
MLSC600A-SB3Z/MRH600A-B3Z

Notice
The installation section of this manual is designed for qualified persons only.
Be sure to read the operating section before conducting operation in order to
prevent unit damage and unnecessary accidents.
The contents of this manual are subject to change without prior notice for
further improvement of related models.
The product introduced in this manual is in compliance with
GB/T18430.1-2007.
Report to and register in the local corresponding administrative organization
before and after operating the pressure vessel unit.
The air source screw water chiller unit is designed based on the following
conditions:
Refrigeration Condition
Water side outlet temperature 5℃-15℃
Air side inlet temperature 10℃-43℃
警告
Personnel must be fully acquainted with the operation manual before operating
the refrigerant system.
Warning
!

Safety Warning
The MLSC_A series units adopt the R134a refrigerant, which is the mid-pressure
medium and liquefied gas. The saturated vapor pressure of R134a refrigerant corresponds
to the temperature. That is, if the temperature is high and the corresponding saturated
vapor pressure is high too. To ensure the safety of units, the ambient temperature cannot be
higher than 43°C during the downtime of units. Otherwise, you should start the chilled water
pump to decrease the temperature of the evaporator. When the unit is charged with
refrigerant, it is forbidden to perform flame-cut or welding operations on the shell and tube
heat exchanger, finned heat exchanger, reservoir, and unit pipes. When the unit
operates or bears the pressure, it is forbidden to fasten bolt or nut. If contact surfaces leak,
you can fasten the bolt and nut only after the pressure is released. Avoid refrigerant
leakage in case of unit debugging and usage. The R134a vapor concentration (AEL) in
the air that human body can accept is 1000 ppm. It has no adverse impact on human
body within the specified vapor concentration. R134a vapors are concentrated near the
low ground when large spills or leakages occur, which may cause hypoxia and make
you feel uncomfortable. In this case, improve ventilation or blast air by using fan coil to
keep the air near the ground in circulation. Do not enter the polluted area until the refrigerant
vapor is discharged, avoiding the adverse impact. The liquid refrigerant cannot be contacted
with skin and eyes to avoid frostbite.
Pay more attention to the following conditions to ensure safety when using this series of units
in closed areas:
Install outlet pipes and ventilating pipes outdoors and keep away from the air inlet.
Keep sufficient ventilation and use auxiliary ventilating devices to remove refrigerant
vapor leaked accidentally if necessary.
If applicable, connect the outlet of safety valve to the outdoors by using pipes.
If applicable, install the air detector to monitor the refrigerant vapor concentration in the
air.
Other precautions:
Be sure to read and strictly comply with safety requirements.
Please keep this manual carefully for future reference and read it carefully before
operation.
Ensure that controllers are properly connected to the ground and frequently check
whether it is stable, because poor earthing may result in electric shock.
Please abide by the principle of electricity separation.
Please install the unit according to the wiring diagram.Do not use sharp objects to press
the touch screen or put excess stress on the touch screen, avoiding touch screen

damage.
Do not drag and distort power cables and communication lines, avoiding major failure.
Please wring the cloth dampened with neutral water, and wipe the unit to remove fouling.
Do not use acidic, alkaline chemicals.
If fire breaks out accidentally, you should immediately shut down the main power and use
fire extinguisher applicable to oil fire and electric fire.
The units cannot be used in explosive environment.
Please contact the manufacturer if you need to repair the unit. Do not repair it by yourself.

Contents
1 Introduction................................................................................................................. 1
1.1 Function...............................................................................................................1
1.2 Features...............................................................................................................1
1.3 Product Components...........................................................................................2
2Model, Specifications, and Application Range............................................................ 7
2.1 Specifications.......................................................................................................7
2.2 Application Range..............................................................................................10
3.
Evaporator Pressure Drop Curve ............................................................................ 10
4.
Accessories and Models with Special Features........................................................11
4.1 Standard Accessories ........................................................................................11
4.2 Optional Accessories .........................................................................................11
4.3 Models with Special Features............................................................................11
5Operating Principle................................................................................................... 12
6Installation ................................................................................................................ 13
6.1 Loading/Unloading and Hoisting (Diagram).......................................................13
6.2 Requirements for Foundation Installation and Diagrams of Foundation ............15
6.3 Installation Space and Appearance....................................................................19
6.4 Requirements for Water System Installation and Recommended Diagram for the Water
System..............................................................................................................45
6.5 Electrical Installation..........................................................................................48
7Commissioning......................................................................................................... 66
7.1 Check Before Commissioning............................................................................66
7.2 Commissioning Operations................................................................................67
8Daily Use of the Unit................................................................................................. 69
8.1 Check Before Use..............................................................................................69
8.2 Unit Startup Sequence.......................................................................................69
8.3 Unit Stop Sequence...........................................................................................69
8.4 Control Interface Structure.................................................................................70
8.5 Operation...........................................................................................................71
8.6 Fault Alarm Function..........................................................................................87
8.7 Safety Protection Flowchart...............................................................................90
8.8 Precautions for Unit Operation.........................................................................102
9. Troubleshooting................................................................................................... 103
10Maintenance and Service ..................................................................................... 105
10.1 Normal Operating Pressure ...........................................................................105

10.2 Cleaning the Shell-and-Tube Heat Exchanger...............................................106
10.3 Procedure for Replacing the Dry FilterElement..............................................108
10.4 Lubricant........................................................................................................108
10.5 Charging and Evacuating Refrigerants ..........................................................108
10.6 Routine Maintenance Items ...........................................................................109
10.7 Safety Requirements for Maintaining the Water Chiller Unit .......................... 111

Air Source Screw Water Chiller Unit – Installation Operation and Maintenance Manual
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1 Introduction
1.1 Function
The air source screw water chiller unit has been forging ahead at the forefront of air-cooled unit. It
saves various auxiliary parts such as cooling tower, cooling pump, and corresponding pipe systems.
Featuring simple system structure, it saves installation space. In addition, it saves energy and can be
maintained and managed conveniently. Therefore, it is especially suitable for the area lack of water. The
indoor unit of air source screw water chiller unit adopts the semi-closed twin-screw compressor with
advanced technology, low noise, and high efficiency. The twin-screw compressor can deliver the optimal
performance when it is used with the evaporator and condenser that are efficient in heat exchange. The
outdoor unit adopts refrigerating pipes design and free of anti-freezing fluid. Condenser fins with high
effective and low noise fan are placed on the condensing pipes based on a certain gap. The unit framework
adopts steel structure with anticorrosive paint on the surface to ensure the reliability and performance
during unit operation.
The air source screw water chiller unit is transported to the site in split mode. The refrigerant pipes of
indoor units have been properly assembled before delivery, and charged with the necessary refrigerants
and lubricants. The air source screw water chiller unit adopts twin-screw compressor designed with the
most advanced, industrial third-generation asymmetric technology of 5 gear teeth to 6 gear teeth. The
detailed functions are as follows:
Variable capacity adjustment, high efficiency, and energy saving.
Human-orientated micro-computer control system with remote control function.
Ten self-protection functions to ensure the safe and reliable operation.
This full series of units have diversified models and can be customized for you.
The company adheres to the customer-driven design concept to meet customer’s various requirements.
This series of units features compact structure, small size, low noise, high COP, long service life, easy
operation and maintenance, and other advantages. Therefore, they are widely used in multiple scenarios
such as hotels, restaurant, office buildings, shopping malls, hospitals, etc. In addition, they are applicable
to air conditioning scenarios such as metallurgical, chemical, mechanical and electronic industry.
1.2 Features
1.2.1 Simple and Economic Apparatus
(1) The compact appearance makes this series of units widely used for various buildings, saving the
space for the equipment room.
(2) The bolt joints allow you to rapidly and conveniently assemble and disassemble the units.
(3) Lightweight design simplifies the operation requirements and reduces installation time and cost.
(4) Units have been charged with refrigerants and lubricants before delivery, which reduces the onsite

Air Source Screw Water Chiller Unit – Installation Operation and Maintenance Manual
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workload, material, and installation cost.
(5) Customers only need to connect the refrigerant pipes, evaporator water pipes, and power cables
between outdoor units and indoor units to use the units, simplifying the entire installation process.
(6) The split design of units is free of larger installation base, and removes the oil cooler and related
purification systems, reducing the unit weight. In addition, outdoor units can be installed far away from
the master unit, reducing operation noise.
(7) The unit is tested under various conditions before its delivery.
(8) The unit is directly driven. In addition, it operates in a high efficient and reliable way with fewer
movable components. Therefore, it can be easily maintained and serviced.
(9) The unit is easily installed without requiring a cooling tower. It releases heat to the air when it is in
cooling mode without requiring a cooling tower and cooling pump. Therefore, it is especially suitable
for water-deficient areas. The indoor unit requires a dedicated equipment room. The outdoor unit can
be installed on the rooftop, ground and other outdoor places.
1.2.2 Technical State and Precise Control
(1) The unit is fitted with sensors and other components related to control before delivery, and it has been
tested.
(2) Smart control: Adopts micro-computer controller featuring various automatic control functions such as
fault diagnosis, and energy management and monitoring, which ensures efficient running and easy
operation of the unit. The unit provides the RS485 communication interface, which allows the host
computer to control startup/stop of the unit, minimizing the operation cost.
(3) Complete safety control system: Electrical control elements are of world well-known brands with stable
quality and reliable performance. In addition, units are designed with multiple safety protections
including high/low pressure, oil differential pressure, antifreeze, water flow volume, anti-phase, and
overload, which ensures safe and reliable operation of the unit.
1.2.3 Reliability and Ease Maintenance
(1) The unit is directly driven with a low rev and ease maintenance. In addition, it operates in high efficient
and reliable way with less movable components.
(2) The unit is in stable performance by using the electronic expansion valve technology.
1.2.4 Easy Installation and Simple Structure
The unit has been subject to comprehensive commissioning before delivery, ensuring the reliability of the
unit’s onsite operation. For onsite installations, you just need to connect the unit to the supply power,
refrigerant pipe, and water source. Then the unit starts to work after simple installation and debugging.
Additionally, the unit is easy to operate and fitted with automatic protection and adjustment apparatus,
which facilitates the management.
1.3 Product Components

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1.3.1 Compressor
(1) The unit adopts twin-screw compressor designed with the most advanced, industrial third-generation
asymmetric technology of 5 gear teeth to 6 gear teeth. The screw rotor is a patented product based on
effective improvement of the German GHH rotor profile. The male and female rotors are designed by
using CNC high-precision screw rotor processing equipment, which allows each component to evenly
distribute and work in gapless. This minimizes the frictional resistance and ensures the low sound
operation and long service life. Compared with single screw compressor, the twin-screw compressor
features gapless loss, efficiency in capacity, low noise, and fewer quick-wear parts, which has got the
British and American patents.
(2) The differential pressure fuel helps optimize the performance of each movable component in the
compressor to achieve the optimal lubrication result without extra oil pump. This saves the complex oil
system and makes the entire system simple. Therefore, the maintenance is more convenient and
operation is more reliable.
(3) The special high-precision zero clearance bearing ensures the long service life of units.
(4) The SKF compressor bearing from Sweden with long service life is used, ensuring that the screw
master units can continuously work more than 30,000 hours for a long term.
1.3.2 Evaporator
Shell-and-tube evaporator adopts high-efficiency heat transfer tubes and special tube layout design. It fully
considers the state change, the flow velocity, the pressure drop of the refrigerant in refrigerant condition to
ensure sufficient evaporation and strengthen the refrigerating capacity.
1.3.3 Condenser
Copper-fin heat exchanger adopts high- efficiency heat transfer tubes with the feature of high efficiency
and so on. The unit is able to adjust the capacity matching with load change to improve the efficiency of
compressor, reduce the energy consumption, and increase the unit’s service life.
Fans featuring low noise, stable operation, and slight shaking are installed on the top of condensers,
generating low noise and high power.
Aluminous-fin cupreous corrosion resistant tubes are cross banding to supply high coefficient of heat
transfer.
1.3.4 Safety Valve

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The safety valve of units helps release the dangerous high pressure. To avoid device damage and personal
injury, these apparatuses must work in the optimal status.
Therefore, it is necessary to perform the following maintenance tasks:
(1) Disassemble the eduction pipe of the outlet value at least once a year to check whether corrosion, rust,
dust, scale deposit, and leakage are found inside the value.
(2) Replace the safety valve instead of repairing it, if corrosion and foreign matter are found.
(3) Check the valve more frequently if the unit is installed in corrosive environment or the safety valve
discharges air into corrosive environment.
1.3.5 Economizer
For units with economizer, the cooling capacity and efficiency will be improved through the cooling
circulation or two-step cooling circulation. The energy saving effect is noticeable especially at high
condensing temperature and low evaporation temperature. The unique economizer access port of screw
compressor directly takes the gaseous liquid back to the compressor in the optimum compression ratio for
recompression.
1.3.6 Liquid Injection System
The two-step liquid injection system avoids the superheat in case of compressor overload. In addition, the
flexible control mode reduces the impact on the energy efficiency of units.
1.3.7 Smart Control
(1) The unit adopts micro-computer controller featuring various automatic control functions such as fault
diagnosis, energy management, and antifreeze monitoring, which ensures efficient running and easy
operation of the unit. The unit features built-in RS485 communication interface, and multiple units can
be controlled through interconnection. With the RS485/RS232 switching interface program, the unit
can be controlled by the host computer. The host computer controls the startup/stop of units based on
the load requirement and operating time.
(2) Multiple self-protections ensure the unit’s safe and reliable operation.

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1.3.8 Variable Capacity Adjustment, High Efficiency, and Energy Saving
The high-precision capacity control valve traces the unit’s load changes and adjusts the refrigerant volume.
The capacity adjustment can adopt four-step control mode (25%, 50%, 75%, and 100%) or stepless
adjustment (this function must be noted on the order), which saves operating cost for customers.
Capacity
output
Four-step capacity adjustment
Stepless capacity adjustment
Capacity
requirement
Capacity adjustment curve
Capacity adjustment diagram for compressor

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2Model, Specifications, and Application Range
2.1 Specifications
2.1.1 Nominal Cooling Capacities
Indoor Unit
Model
MLSC380A-SB3Z MLSC500A-SB3Z MLSC600A-SB3Z
Cooling capacity kW 380 496 594
Cooling input power kW 124 159 187
Compressor
Type Semi-hermetic twin-
screw
compressor Semi-hermetic twin-
screw
compressor Semi-hermetic twin-
screw
compressor
Quantity 1 1 1
Energy adjustment mode Automatic
Energy adjustment range (%) (25%, 50%, 75%,100%)
Refrigerant
Name R134a
Charge (kg) 80 96 135
Power supply Three-phase five-wire system
380V/3P+N+PE/50Hz
Safety protection High pressure/Low pressure/Low water flow/Antifreeze/Motor overload
/Low
voltage/Open-phase protector/Phase sequence/Oil heater/Safety valve/Oil level
Water side
heat
exchanger
Type Shell-and-tube heat exchanger
Water volume
(t/h) 65 86 102
Water
side
pressure drop
(kpa) 50 55 60
Inlet/outlet pipe
diameter (mm) DN125
Water side fouling factor
(m2.k/kw) 0.086 (m2.k/kw)
Unit dimensio
ns
(mm)
Length 3300 3500 3500
Width 1200 1200 1200
Height 1830 2113 2130
Unit weight (kg) 2586 2790 3020
Running weight (kg) 2786 2990 3220
Notes:

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(1) Nominal cooling capacities are based on the following conditions: Chilled water inlet/outlet
temp: 12°C/7°C; Indoor temp: 35°C.
(2) Only performance parameters of the basic module are listed. You can obtain performance
parameters of unit combinations by referencing the listed parameters.
(3) The design pressure on the chilled water side is 1.0 Mpa.
(4) The preceding specifications may be changed due to continuous improvement of products.
The specifications on product nameplates and physical objects shall prevail.
(5) The“
““
“Cooling input power”
””
”item include fan power.

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Outdoor Unit
Model
MRH380A-B3Z MRH500A-B3Z MRH600A-B3Z
Power supply Three-phase five-wire system
380V/3P+N+PE /50Hz
Air side
heat
exchanger
Type Internal threaded pipes + aluminum fins
Fan Quantity 6 8 10
Air volume (m3/h) 23000x6 23000x8 23000x10
Motor input power (kW) 2.4x6 2.4x8 2.4x10
Unit
dimensio
ns
(mm)
Length 3500 4491 5600
Width 2280 2280 2280
Height 2370 2370 2370
Unit weight (kg) 1360 2070 2390
Running weight (kg) 1380 2090 2410
Notes:
(1) Nominal cooling capacities are based on the following conditions: Chilled water inlet/outlet
temp: 12°C/7°C; Outdoor temp: 35°C.
(2) Only performance parameters of the basic module are listed. You can obtain performance
parameters of unit combinations by referencing the listed parameters.
(3) The design pressure on the chilled water side is 1.0 Mpa.
(4) The preceding specifications may be changed due to continuous improvement of products.
The specifications on product nameplates and physical objects shall prevail.

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2.2 Application Range
Content Running Range
Ambient temp. 10°C–43°C
Outlet water temp. 5°C–15°C
Water flow volume Rated flow volume±20%
Max inlet/outlet water temp. difference 8°C
Voltage tolerance Rated voltage±10%
Phase tolerance ±2%
Power supply frequency Rated frequency±2%
Evaporator max working pressure on water side 1.0 MPa
Compressor max. start count 6 times/h
Environment quality High corrosive environment and high
humidity should be avoided.
Drainage system
The height of water drainage should
not be higher than the base of the unit
on the spot.
3. Evaporator Pressure Drop Curve
0
20
40
60
80
100
120
0 20 40 60 80 100 120 140 160
MLSC380A-SB3Z
MLSC500A-SB3Z
MLSC600A-SB3Z
Evaporator
Water Flow /m
3
·h
-1
Evaporator
Water Press re Drop /Pa
Evaporator
Water Press re Drop C rve

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4. Accessories and Models with Special Features
4.1 Standard Accessories
S/N Name Unit Quantity Specifications
1 Product certificate Piece 1
2 User manual Piece 1
3 Water flow controller Piece 1 G1"
4 Packing list Piece 1
4.2 Optional Accessories
S/N Name Unit Quantity Specifications
1 Water switch Piece As required by customers
2 Spring shock absorber Piece See the foundation diagram
in section 7.2.2.
4.3 Models with Special Features
Certain models with special features can provide specific functions to meet various requirements of
customers.
S/N Type Function Contents of Order
1 High-temperature
refrigerating unit
The maximum allowed ambient
temperature for refrigerating is 48°C.
The maximum ambient
temperature is specified.
2 Ultra-temperature unit
The maximum allowed ambient
temperature for refrigerating is 56°C.
The maximum ambient
temperature is specified.
3 Partial heat-recovery unit
The heat of condensation released by the
unit that can be partially recovered.
The heat recovery
capacity is specified.

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5Operating Principle
Air source screw water chiller comprises five major components including the compressor, finned heat
exchanger, electronic expansion valve, shell-and-tube heat exchanger, and electric control system, and
some auxiliaries such as the economizer. The basic circulation principle of the unit is shown in the following
figure.
Operating principle of MLSC_A series units

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6Installation
6.1 Loading/Unloading and Hoisting (Diagram)
(1) Units should be loaded and unloaded carefully to avoid causing damage to unit components. Use a
crane to load and unload units and use a forklift for short-distance transportation. A skid can ensure
that the weight of units is evenly distributed on the base. In addition, three to six steel rods can be
placed under the unit base to help slowly move the units, as shown in the following figure.
Diagram for horizontal movement
Units
Steel rod Skid
(2) To hoist the units, pay attention to the following instructions:
Choose a suitable crane based on the unit's weight (buy insurance for it if possible).
Hoist the unit by using the method shown in the following figure. The steel rope shall wind the
lifting hook one circle to prevent danger due to steel rope slipping when the weight is unbalanced.
Use an enlargement pole to prevent sling damage to the unit.
Strictly abide by the local safety regulations during hoisting. Only relevant personnel are allowed
within the construction area. It is forbidden to stand under the crane or the lifted units.

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Indoor units hoisting
Outdoor units hoisting

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6.2 Requirements for Foundation Installation and Diagrams of Foundation
6.2.1 Requirements for Foundation Installation
Air-cooled screw units should be installed outdoors, for example, on the rooftop, ground, or near the
buildings. Units must be installed on a solid foundation. A block of concrete slab is recommended, whose
load-bearing capacity must be sufficient to withstand all the units, as well as the weight of maintenance
personnel.
A spring shock absorber must be installed between the unit base and the foundation to avoid unit vibration
and to prevent noise during unit installation. The position for placing the spring shock absorber and the
points for load bearing are shown in the following figure.