Midea LSBLG320/MZ, LSBLG255/MZ, LSBLG400/MZ, LSBLG630/MZ, LSBLG860/MZ Service Manual

LSBLG***/MZ

Model:

Technical Service Manual

Water-cooled

Screw Chiller

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

1

Contents

Ⅰ. Safety precautions ....................................................................................................... 2

1. Installation safety considerations .................................................................................................... 2

2. Maintenance safety considerations ..................................................................................................... 3

3. Repair safety considerations ................................................................................................................ 4

Ⅱ. Product .......................................................................................................................... 6

1.General information .................................................................................................................................. 6

2. Features ................................................................................................................................................... 8

3. Specifications .......................................................................................................................................... 10

4.Outline Dimension ................................................................................................................................... 12

5.Refrigeration system .............................................................................................................................. 13

6. Major System Components.................................................................................................................. 17

7.Water Flow ................................................................................................................................................. 21

8. Unit sound levels .................................................................................................................................... 25

9. Compressor oil........................................................................................................................................ 25

10. Recommend breaker current ............................................................................................................ 25

11.Operating Range .................................................................................................................................... 26

12.Capacity table ......................................................................................................................................... 28

13. Accessories ........................................................................................................................................... 33

Ⅲ. Control ........................................................................................................................ 34

1. Control Flow Chart ................................................................................................................................. 34

2. Energy Adjustment ................................................................................................................................ 35

3. Start/stop process .................................................................................................................................. 36

4. Sensors ..................................................................................................................................................... 37

5. Parts control ............................................................................................................................................ 39

6. Operation Part ......................................................................................................................................... 46

7. Safety protection .................................................................................................................................... 61

Ⅳ.Electrical control ................................................................................................ ......... 63

1.Electrical data ........................................................................................................................................... 63

2. Electrical components introduction .................................................................................................. 63

3.Electrical Parts parameter setting ....................................................................................................... 65

4.Field wiring ................................................................................................................................................ 68

Ⅴ. Installation .................................................................................................................. 73

1. Unit installation ....................................................................................................................................... 73

2. Water Pipeline System installation .................................................................................................... 76

3.Wiring installation ................................................................................................................................... 83

Ⅵ. Commissioning ....................................................................................................... 85

1.Pre start-up ................................................................................................................................................ 85

2. Start-up ...................................................................................................................................................... 89

Ⅶ. Maintenance ............................................................................................................... 92

1. Daily maintenance .................................................................................................................................. 92

2. Maintenance ............................................................................................................................................. 97

Ⅷ. Troubleshooting ....................................................................................................... 103

1.Protection items ..................................................................................................................................... 103

2.Troubleshooting ..................................................................................................................................... 106

Ⅸ. Appendix 1 ................................................................................................................ 108

Manufacture reserves the right to discontinue, or change at any time, specifications or designs without
notices and without incurring obligations.

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

2

Ⅰ. Safety precautions

Before use, read through the operating instructions to ensure proper using. Please keep it well so that
the professional technician can refer to it anytime.

1. Installation safety considerations

Access to the unit must be reserved to authorized personnel, qualified and trained in monitoring and
maintenance. The access limitation device must be installed by the customer (e.g. cut-off, enclosure).
After the unit has been received, when it is ready to be installed or reinstalled, and before it is started up,
it must be inspected for damage. Check that the refrigerant circuit(s) is (are) intact, especially that no
components or pipes have shifted (e.g. following a shock). If in doubt, carry out a leak tightness check
and verify with the manufacturer that the circuit integrity has not been impaired. If damage is detected
upon receipt, immediately file a claim with the shipping company. Midea strongly recommends
employing a specialized company to unload the machine.

It is compulsory to wear personal protection equipment. Do not remove the skid or the packaging until
the unit is in its final position. These units can be moved with a fork lift truck, as long as the forks are
positioned in the right place and direction on the unit.

The units can also be lifted with slings, using only the designated lifting points marked on the unit. Use
slings with the correct capacity, and always follow the lifting instructions on the certified drawings
supplied with the unit. Safety is only guaranteed, if these instructions are carefully followed. If this is not
the case, there is a risk of material deterioration and injuries to personnel. Never cover any safety
devices. This applies to the relief valve(s) in the refrigerant circuit(s). Ensure that the valves are correctly
installed, before operating the unit.

The relief valves are designed and installed to ensure protection against overpressure caused by fire.
The relief valve must only be removed if the fire risk is fully controlled and after checking that this is
allowed by local regulations and authorities. This is the responsibility of the operator. If the unit is
installed in a room, the safety valves must be connected to discharge pipes.

Note:

(1) These pipes must be installed in a way that ensures that people and property are not exposed to
refrigerant leaks. These fluids may be diffused in the air, but far away from any building air intake, or they
must be discharged in a quantity that is appropriate for a suitably absorbing environment. It is
recommended to install an indicating device to show if part of the refrigerant has leaked from the valve.

(2) The presence of oil at the outlet orifice is a useful indicator that refrigerant has leaked. Keep this
orifice clean to ensure that any leaks are obvious. The calibration of a valve that has leaked is generally
lower than its original calibration. The new calibration may affect the operating range.

(3) To avoid a nuisance tripping or leaks, replace or re-calibrate the valve. Periodic check the relief
valves. Ensure good ventilation, as accumulation of refrigerant in an enclosed space can displace

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

3

oxygen and cause asphyxiation or explosions. Inhalation of high concentrations of vapour is harmful and
may cause heart irregularities, unconsciousness, or death. Vapour is heavier than air and reduces the
amount of oxygen available for breathing. These products cause eye and skin irritation. Decomposition
products are hazardous.

2. Maintenance safety considerations

2.1 Engineers safety consideration

Engineers working on the electric or refrigeration components must be authorized, trained and fully
qualified to do so. All refrigerant circuit repairs must be carried out by a trained person fully qualified to
work on these units. He must have been trained and be familiar with the equipment and the installation.
All welding operations must be carried out by qualified specialists.

The insulation must be removed and heat generation must be limited by using a wet cloth. Any
manipulation (opening or closing) of a shut-off valve must be carried out by a qualified and authorized
engineer. These procedures must be carried out with the unit shut-down.

Note:

(1) During any handling, maintenance and service operations the engineers working on the unit must
be equipped with safety gloves, glasses, shoes and protective clothing.
(2) Never work on a unit that is still energized.
(3) Never work on any of the electrical components, until the general power supply to the unit has been
cut using the disconnect switch in the control box.
(4) If any maintenance operations are carried out on the unit, lock the power supply circuit ahead of the
machine.
(5) If the work is interrupted, always ensure that all circuits are still de-energized before resuming the
work.
Attention: Even if the unit has been switched off, the power circuit remains energized, unless the unit or
circuit disconnect switch is open. Refer to the wiring diagram for further details. Attach appropriate safety
labels.

2.2 Operating checks:

Important information regarding the refrigerant used:

 Refrigerant type: R22
 Periodic inspections for refrigerant leaks may be required depending on local legislation. Please

contact your local dealer for more information.
 During the life-time of the system, inspection and tests must be carried out in accordance with

national regulations.

2.3 Safety device checks:

 The safety devices and external overpressure devices (safety valves) must be checked on site
regularly.

 At least once a year thoroughly inspect the protection devices (valves). If the machine operates in
regularly carry out leak tests and immediately repair any leaks.

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

4

 Ensure regularly that the vibration levels remain acceptable and close to those at the initial unit
start-up. Before opening a refrigerant circuit, purge and consult the pressure gauges.

 Change the refrigerant when there are equipment failures, following related regulations or carry out
a refrigerant analysis in a specialist laboratory.

 If the refrigerant circuit remains open for longer than a day after an intervention (such as a
component replacement), the openings must be plugged and the circuit must be charged with nitrogen
(inertia principle). The objective is to prevent penetration of atmospheric humidity and the resulting
corrosion on the internal walls and on non-protected steel surfaces.

3. Repair safety considerations

Note: It is compulsory to wear personal protection equipment. The insulation must be removed and

warming up must be limited by using a wet cloth. Before opening the unit always ensures that the circuit
has been purged.

 All installation parts must be maintained by qualified and skilled technicians, in order to avoid
material deterioration and injuries to people. Faults and leaks must be repaired immediately. The
authorized technician must have the responsibility to repair the fault immediately. Each time repairs have
been carried out to the unit, the operation of the safety devices must be re-checked.

 Comply with the regulations and recommendations in unit and installation safety standards. If a leak
occurs or if the refrigerant becomes contaminated (e.g. by a short circuit in a motor) remove the
complete charge using a recovery unit and store the refrigerant in mobile containers.

 Repair the leak detected and recharge the circuit with the total R22 charge, as indicated on the unit
name plate. Certain parts of the circuit can be isolated. Only charge liquid refrigerant R22 at the liquid
line. Ensure that you are using the correct refrigerant type before recharging the unit. Charging any
refrigerant other than the original charge type R22 will impair machine operation and can even lead to a
destruction of the compressors. The compressors operating with this refrigerant type are lubricated with
synthetic oil.

 Do not use oxygen to purge lines or to pressurize a machine for any purpose. Oxygen gas reacts
violently with oil, grease, and other common substances.

 Never exceed the specified maximum operating pressures. Verify the allowable maximum high- and
low-side test pressures by checking the instructions in this manual and the pressures given on the unit
name plate.

 Do not use air for leak testing. Use only refrigerant or dry nitrogen.
 Do not unweld or flame cut the refrigerant lines or any refrigerant circuit component until all

refrigerant (liquid and vapour) has been removed from chiller. Traces of vapour should be displaced with
dry air nitrogen. Refrigerant in contact with an open flame produces toxic gases.

 The necessary protection equipment must be available, and appropriate fire extinguishers for the
system and the refrigerant type used must be within easy reach.

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

5

 Do not siphon refrigerant. Avoid spilling liquid refrigerant on skin or splashing it into the eyes. Use
safety goggles. Wash any spills from the skin with soap and water. If liquid refrigerant enters the eyes,
immediately and abundantly flush the eyes with water and consult a doctor.

 Never apply an open flame or live steam to a refrigerant container. Dangerous overpressure can
result. If it is necessary to heat refrigerant, use only warm water.

 During refrigerant removal and storage operations follow applicable regulations. These regulations,
permitting conditioning and recovery of halogenated hydrocarbons under optimum quality conditions for
the products and optimum safety conditions for people, property and the environment.

 Any refrigerant transfer and recovery operations must be carried out using a transfer unit. The units
must never be modified to add refrigerant and oil charging, removal and purging devices. All these
devices are provided with the units. Please refer to the certified dimensional drawings for the units.

 Do not re-use disposable (non-returnable) cylinders or attempt to refill them. It is dangerous and
illegal. When cylinders are empty, evacuate the remaining gas pressure, and move the cylinders to a
place designated for their recovery. Do not incinerate.

 Do not attempt to remove refrigerant circuit components or fittings, while the machine is under
pressure or while it is running. Be sure pressure is at 0 kPa before removing components or opening a
circuit.

 Do not attempt to repair or recondition any safety devices when corrosion or build-up of foreign
material (rust, dirt, scale, etc.) is found within the valve body or mechanism.

 If necessary, replace the device. Do not install safety valves in series or backwards.

ATTENTION: No part of the unit must be used as a walkway, rack or support. Periodically check and

repair or if necessary replace any component or piping that shows signs of damage. The refrigerant lines
can break under the weight and release refrigerant, causing personal injury. Do not climb on a machine.
Use a platform, or staging to work at higher levels.
 Use mechanical lifting equipment (crane, hoist, winch, etc.) to lift or move heavy components. For
lighter components, use lifting equipment when there is a risk of slipping or losing your balance.

 Use only original replacement parts for any repair or component replacement.
 Do not drain water circuits containing industrial brines, without informing the technical service

department at the installation site or a competent body first.
 Close the entering and leaving water shut off valves and purge the unit water circuit, before working

on the components installed on the circuit (screen filter, pump, water flow switch, etc.).

 Do not close the water box bolts until the water boxes have been completely drained.
 Periodically inspect all valves, fittings and pipes of the refrigerant and hydraulic circuits to ensure

that they do not show any corrosion or any signs of leaks.
 It is recommended to wear ear defenders, when working near the unit and the unit is in operation.

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

6

Ⅱ. Product

1.General information

1) .Product Lineup

2). Nomenclature

Series

Model

Power
supply

Cooling

Capacity (kW)

Compressor

Single head

LSBLG255/MZ

380V/3N/50Hz

253

1

LSBLG320/MZ

380V/3N/50Hz

318

1

LSBLG400/MZ

380V/3N/50Hz

400

1

LSBLG485/MZ

380V/3N/50Hz

485

1

LSBLG630/MZ

380V/3N/50Hz

628

1

LSBLG860/MZ

380V/3N/50Hz

859

1

Dual heads

LSBLG970/MZ

380V/3N/50Hz

970

2

LSBLG1060/MZ

380V/3N/50Hz

1057

2

LSBLG1260/MZ

380V/3N/50Hz

1256

2

LSBLG1490/MZ

380V/3N/50Hz

1487

2

LS B 255

/M C LG

LS: Water chiller

B: Semi-hermetic

LG: Screw type compressor

255: Nominal cooling capacity

Design sequence code

C: R134a; omit for R22

Z

Z: Factory code

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

7

3). External Appearance

LSBLG255/MZ~ LSBLG860/MZ

LSBLG970/MZ~ LSBLG1490/MZ

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

8

2. Features

Leading technology of twin screw compressor

 Midea screw chiller is equipped with the 3rd generation industrial

compressor that has the latest advanced 5-6 asymmetry dentiform
semi-hermetic screw rotors.

 The rotors are processed by high-precision CNC and each part is

well-proportioned and none-gap matched, which minimizes the friction
resistance and clearance lost and also guarantees quiet running and
good duration.

High efficiency, energy saving

 Extremely high full load and partial load energy efficiency.
 New twin-rotor screw compressor equipped with a high-efficiency motor and a variable capacity

valve that can adjust the capacity of 25%, 50%, 75% and 100% in 4 stages (Stepless control as an
option) and permits exact matching of the cooling capacity to the actual load.

 A decrease in chiller energy costs, particularly at the part-load conditions at which the chiller

operates most of the time.

Outstanding reliability

 Full factory testing of the unit with water hookup helps provides a trouble-free start-up.
 Extensive quality control checks during testing means that each equipment protection and operating

control is properly adjusted and operates correctly before it leaves the factory.

 Transport simulation test in the laboratory on a vibrating table.
 Factory-installed options minimize field expenses and startup labor.

Intelligent control, easy operation

 Microprocessor control as standard on all the units. A display

illustrates the machine’s operation status and programmable

parameters (set point) e.g. water temperature and refrigeration
pressure and temperature, allowing the operator to determine the
unit status and also allow changes to various set points. The control
system adopts PCB with predictive logic to select the most energy efficient combination of
compressors.

Easy and fast installation

 The unit has passed full factory test before being delivered to ensure the reliable working on the

site. The unit can be placed in service only after being connected with power and water supply
during field installation.

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

9

 The installation and adjustment are simple .Standard flange connection and wire mesh to the

electrical panel. Refrigerant and lubrication oil are provided to the unit in the factory. Only piping
connection and power supply connection are required on the site.

Wide application range

 Water cooled screw chiller are widely applied in school, hospital, shopping mall, office as well as the

factory and manufacturing processing area.

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

10

3. Specifications

Single head

LSBLGXXX/MZ

255

320

400

485

630

860

Cooling capacity

kW

253

318

400

485

628

859

Power input

kW

53.6

67

85

100

125

173

EER

kW/kW

4.73

4.75

4.71

4.85

5.02

4.97

Semi-hermetic screw compressor

Circuit A

Quantity 1 1 1 1 1 1

Circuit B

Quantity

--

--

--

--

--

--

Capacity Control

%

25%,50%,75%,100% four steps control

(25%,50%-100% Stepless as Option)

Oil recharge

Type

HBR-B01

Circuit A

L

14

14

15

18

23

28

Circuit B

L

--

--

--

--

--

--

Refrigerant

Type

R22

Circuit A

kg

35

40

60

80

110

160

Circuit B

kg

--

--

--

--

--

--

Control Type

TXV

TXV

TXV

TXV

TXV

EXV

Evaporator

Type

Shell-tube Direct Expansion Evaporator

Water content

L

100

150

80

120

340

290

Water flow

m³/h

43.5

54.7

68.8

83.4

108

147.7

Pressure drop

kPa

41

36

73

54

65

65

Connection Type

Victaulic coupling

Max. pressure

MPa 1 1 1 1 1 1

Water inlet/outlet pipe dia.

mm

80

80

100

125

125

150

Condenser

Type

Tube-and shell condenser

Water content

L

150

150

130

160

320

260

Water flow

m³/h

54.4

68.4

86

104.3

135

184.7

Pressure drop

kPa

36

41

22

49

81

41

Max. pressure

MPa 1 1 1 1 1 1

Water inlet/outlet pipe dia.

mm

80

80

100

125

125

150

Unit length

mm

2800

2800

2860

3200

3430

3430

Unit width

mm

1165

1165

1285

1300

1480

1610

Unit height

mm

1350

1350

1420

1450

1600

1730

Shipping weight

kg

1540

1870

2250

2610

2975

3780

Running weight

kg

1840

2070

2550

2910

3375

4180

Safety protection device

The following safety devices are equipped as standard.
High pressure (pressure switch);Low pressure (pressure sensor)
Compressor thermal protection
High discharge temperature on the compressor
Phase monitor; Low-pressure ratio; Low oil level protection
Interrupter protection ;Overload compressor protection
Over-voltage & low- voltage protection
Sensor malfunction protection
Contactor malfunction protection
Freeze protection

Note:

Nominal cooling capacities are based on the following conditions:

Chilled water inlet/outlet temp: 12℃/7℃; (53.6F/44.6F); Cooling water inlet/outlet temperature 30/35℃ (86F/96F).

The design fouling factor for both evaporator and condenser are 0.086 m2. ℃/kW, otherwise can be customized.

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

11

Dual heads

LSBLGXXX/MZ

970

1060

1260

1490

Cooling capacity

kW

970

1057

1256

1487

Power input

kW

200

214

250

298

EER

kW/kW

4.85

4.94

5.02

4.99

Semi-hermetic screw compressor

Circuit A

Quantity 1 1 1 1

Circuit B

Quantity 1 1 1 1

Capacity Control

%

25%,50%,75%,100% four step control

(25%,50%-100% Stepless as Option)

Oil recharge

Type

HBR-B01

Circuit A L 18

18

23

23

Circuit B L 18

23

23

28

Refrigerant

Type

R22

Circuit A

kg

80

80

110

110

Circuit B

kg

80

90

110

130

Control Type

TXV

TXV

TXV

TXV+EXV

Evaporator

Type

Shell-tube Direct Expansion Evaporator

Water content

L

360

530

740

660

Water flow

m³/h

166.8

181.8

216

255.8

Pressure drop

kPa

83

85

87

76

Connection Type

Victaulic coupling

Max. pressure

MPa 1 1 1 1

Water inlet/outlet pipe dia.

mm

150

150

200

200

Condenser

Type

Tube-and shell condenser

Water content

L

360

320

460

430

Water flow

m³/h

208.6

227.3

270

319.7

Pressure drop

kPa

40

99

56

99

Max. pressure

MPa 1 1 1 1

Water inlet/outlet pipe dia.

mm

150

150

200

200

Unit length

mm

4100

4100

4450

4600

Unit width

mm

1630

1740

1780

1810

Unit height

mm

1680

1680

1730

1920

Shipping weight

kg

4630

4870

5840

6490

Running weight

kg

5080

5320

6340

7090

Safety protection device

The following safety devices are equipped as standard.
High pressure (pressure switch)
Low pressure (pressure sensor)
Compressor thermal protection
High discharge temperature on the compressor
Phase monitor; Low-pressure ratio; Low oil level protection
Interrupter protection; Overload compressor protection
Over-voltage & low- voltage protection
Sensor malfunction protection
Contactor malfunction protection
Freeze protection

Note:

Nominal cooling capacities are based on the following conditions:

Chilled water inlet/outlet temp: 12℃/7℃; (53.6F/44.6F); Cooling water inlet/outlet temperature 30/35℃ (86F/96F).

The design fouling factor for both evaporator and condenser are 0.086 m2. ℃/kW, otherwise can be customized.

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

12

4.Outline Dimension

Single head

Chilled Water Inlet

Chilled Water Outlet

Cooling Water Outlet

Cooling Water Inlet

Model

A B C D E F H J K

Cooling

Water

In/outlet

Chilled

Water

In/outlet

LSBLG255/MZ

2800

1165

1350

1600

880

1780

280

210

140

DN80

DN80

LSBLG320/MZ

2800

1165

1350

1600

880

1760

280

210

140

DN80

DN80

LSBLG400/MZ

2860

1285

1420

1600

1000

1780

328

246

160

DN100

DN100

LSBLG485/MZ

3200

1300

1450

1600

1000

1660

330

230

200

DN125

DN125

LSBLG630/MZ

3430

1480

1600

1800

1220

2150

360

260

200

DN125

DN125

LSBLG860/MZ

3430

1610

1730

1800

1360

2120

400

300

200

DN150

DN150

Dual heads

Chilled Water Outlet

Chilled Water Inlet

Cooling Water Outlet

Cooling Water
Inlet

Model

A B C D E F H J K

Cooling

Water

In/outlet

Chilled

Water

In/outlet

LSBLG970/MZ

4100

1630

1680

1800

1440

2120

415

290

200

DN150

DN150

LSBLG1060/MZ

4100

1740

1680

1800

1440

2680

415

290

200

DN150

DN150

LSBLG1260/MZ

4450

1780

1730

2000

1540

3080

415

285

260

DN200

DN200

LSBLG1490/MZ

4600

1810

1920

2000

1640

3080

650

340

260

DN200

DN200

NOTE: Drawings are not contractually binding. Before designing an installation, consult the certified dimensional drawings
supplied with the unit or available on request.
For the positioning of the fixing points, weight distribution and center of gravity coordinates please refer to the dimensional
drawings.

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

13

5.Refrigeration system

For single head unit (LSBLG255~630/MZ)

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

14

For single head unit (LSBLG860/MZ)

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

15

For dual heads unit (LSBLG970~1260/MZ)

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

16

For dual heads unit (LSBLG1490/MZ)

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

17

6. Major System Components
Major components of the unit

(1)Single compressor parataxis type unit

No.

Name

1

Controller

2

Pressure Gauge

3

Compressor

4

Evaporator

5

Safety Valve

6

Condenser

7

Expansion Valve

8

Emergency Stop

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

18

(2) Dual compressors parataxis type unit

No.

Name

1

Controller

2

Pressure Gauge

3

Compressor

4

Evaporator

5

Condenser

6

Expansion Valve

7

Safety Valve

8

Emergency Stop

6.1 Compressor
Advanced twin screw compressor

 Midea screw chiller equipped with the 3rd generation industrial compressor that has the latest
advanced 5-6 asymmetry dentiform semi-hermetic screw rotors. The rotors are processed by
high-precision CNC and each part is well-proportioned and none-gap matching, which minimizes the
friction resistance and clearance lost, guarantees quiet running and good duration.

 Compressors have a infinitely variable control down to 25% of its total capacity. This control is made
by means of capacity slides controlled by microprocessors.

 Standard starter is star-delta type. Infinitely capacity control type is available (as option).

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

19

 With 5-6 asymmetry dentiform, the screw rotor gained patent by improving the shape of German
rotor GHH, proved having good balance, small vibration, and low noise due to balance testing by special
machine. Comparing with normal screw rotor with 4-6 dentiform, heat efficiency of the rotor with male
and female rotor adopting 5-6 dentiform increase by 10-12% and energy saves by 25%, the rotor also
gained British and American patent.

 The bearing of compressor is from SKF, Sweden, the long lifespan of which ensures screw-type
main unit to run continuously more than 50,000 hours.

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

20

 Lubricant:
The lubricant is supplied automatically by pressure difference inside the compressor. It is unnecessary to

add an extra lubricant pump.

 The Oil Separator comes from MANN of Germany and has reliable qualification. The oil content can
be controlled below 3ppm (the oil content treated by oil-gas separator of common like screw-type air
compressor is no less than 8-10ppm). The oil-gas separator amount is double of same kind of other
products. The large oil filtering area reduces refrigerant flux speed, and has better separating affect and
long lifespan by the secondary reflux technology adopted.

6.2 Pressure vessels

6.2.1 General

Monitoring during operation, re-qualification, re-testing and re-testing dispensation:

 Follow the regulations on monitoring pressurized equipment.
 It is normally required that the user or operator sets up and maintains a monitoring and maintenance

file.

 Follow the control programs.
 If they exist follow local professional recommendations.
 Regularly inspect the condition of the coating (paint) to detect blistering resulting from corrosion. To

do this, check a non-insulated section of the container or the rust formation at the insulation joints.
 Regularly check for possible presence of impurities (e.g. silicon grains) in the heat exchange fluids.

These impurities maybe the cause of the wear or corrosion by puncture

 Filter the heat exchange fluid check and carry out internal inspections as described in EN 378-2.
 In case of re-testing please refer to the maximum operating pressure given on the unit nameplate.
 The reports of periodical checks by the user or operator must be included in the supervision and

maintenance file.

6.2.2 Repair

Any repair or modification, including the replacement of moving parts:
 Must follow local regulations and be made by qualified operators and in accordance with qualified

procedures, including changing the heat exchanger tubes.
 Must be made in accordance with the instructions of the original manufacturer. Repair and

modification that necessitate permanent assembly (soldering, welding, expanding etc.) must be made
using the correct procedures and by qualified operators.

 An indication of any modification or repair must be shown in the monitoring and maintenance file.

6.2.3 Corrosion allowances:

Gas side: 0 mm
Heat exchange fluid side: 1 mm for tubular plates in lightly alloyed steels, 0 mm for stainless steel plates

or plates with copper-nickel or stainless steel protection.

6.2.4 Operating life

The evaporator and condenser are designed for: prolonged usage of 20 years for high-quality materials.

6.2.5 Security

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

21

The condenser is equipped with safety valves. And ball valve is connecting safety valve to condenser.
The ball valve maintain full-state, it is closed only when safety valve is opening or replaced.

Ball valve can protect life and property because it can prevent refrigerant from flowing into the air when
safety valve is opening or replaced.

6.2.6 Evaporator

Midea Screw Chiller is equipped with high efficiency shell and tube evaporator that are constructed by
seamless steel tube with anti-corrosive treatment. The evaporator is a direct expansion type with
refrigerant inside the copper tubes and water on the outside. The copper tubes are roll expanded into
carbon steel tube plates.

Constructed with seamless integrally finned copper, the water pipe system makes the evaporator attain
optimal heat exchange efficient. Also they are removable, which makes it available for efficient. Also they
are removable, which makes it available for altering water piping arrangement.

The design working pressure for both evaporator and condenser are 1.0MPa, higher pressure demand
can be customized.

6.2.7 Condenser

Shell and tube operates with refrigerant in shell and water in tubes. Replaceable water tubes are
fabricated from integral finned cooper and mechanically bonded to steel tube sheets. The condenser is
GB151-1999 (Chinese standard) designed, constructed, inspected and stamped. Water side working
pressure is designed for 1.0MPa.

The condenser is used high-efficient tubes to enhance its transfer performance. Meanwhile, the system's
COP can be increased largely by adding the subcooler.

6.2.8 Throttle valve

The chiller is equipped with expansion valve to decompress and expanse refrigerant.

7.Water Flow

Balance the chilled water flow through the evaporator and the condenser water flow through the
condenser. The flow rates must fall between the minimum and maximum values shown in the below
table. Flow rates below the minimum values shown will result in laminar flow which will reduce efficiency,
cause erratic operation of the electronic expansion valve and could cause low temperature cutouts. On
the other hand, flow rates exceeding the maximum values shown can cause erosion on the heat
exchanges water connections and tubes, even piping breaking.

Variable chilled water flow through the heat exchanges while the compressor(s) are operating is not
recommended. The chiller control set points are based upon a constant flow and variable temperature.

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

22

Model

Evaporator water flow rate m3/h

Condenser water flow rate m3/h

Chilled water

minimum

Chilled water

rated

Chilled water

maximum

Cooling water

minimum

Cooling water

rated

Cooling water

maximum

LSBLG255/MZ

31

44

57

38

54

70

LSBLG320/MZ

38

55

71

48

68

88

LSBLG400/MZ

48

69

90

60

86

111

LSBLG485/MZ

58

83

108

74

104

134

LSBLG630/MZ

76

108

140

95

135

176

LSBLG860/MZ

104

148

192

129

184

239

LSBLG970/MZ

117

167

217

146

209

271

LSBLG1060/MZ

127

182

237

159

227

295

LSBLG1260/MZ

151

216

281

189

270

351

LSBLG1490/MZ

179

256

333

224

320

416

Pressure drop
DX type (Evaporator)

Press ure drop (kPa)

Water flow (m3/h)

0

20

40

60

80

100

120

0 50 100 150 200 250

LSBLG255/MZ

LSBLG320/MZ

LSBLG400/MZ

LSBLG485/MZ

LSBLG630/MZ

LSBLG860/MZ

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

23

Press ure drop (kPa)

Water flow (m3/h)

0

20

40

60

80

100

120

140

160

50 150 250 350

LSBLG970/MZ

LSBLG1060/MZ

LSBLG1260/MZ

LSBLG1490/MZ

DX type (Condenser)

0

10

20

30

40

50

60

70

80

90

100

0 50 100 150 200

LSBLG255/MZ

LSBLG320/MZ

LSBLG400/MZ

LSBLG485/MZ

LSBLG630/MZ

LSBLG860/MZ

Pressure drop (kPa)

Water flow (m3/h)

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

24

Press ure drop (kPa)

Water flow (m3/h)

0

20

40

60

80

100

120

140

0 100 200 300

LSBLG970/MZ

LSBLG1060/MZ

LSBLG1260/MZ

LSBLG1490/MZ

System minimum water volume:

It is often necessary to add a buffer water tank to the circuit in order to achieve the required water
volume. The tank itself must be internally baffled in order to ensure proper mixing of the liquid (water or
brine). Water tank volume is large than 1 / 10 whole system water volume at least.

Refer to the examples below.

How to calculate minimum volume in pipeline system:

W=QgT/CP▽t
W — Minimum water volume（kg）；
Qg — Total cooling/heating capacity of the terminal（kW）；
T — Thermal stability time requirement，Take（8～10）×60s；
CP — Water specific heat at constant pressure，4.187kj/（kg·℃）；
▽t — Water temperature fluctuation required value，take 5℃。

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

25

For system, Qg is calculated according to the lowest load so that it operates steadily.
It can also calculated according to 0.5Q(50%). T takes 8 minutes, the shortest time that the unit
running. That is 480s. Cp=4.18kj/kg, ▽t =5℃

According to the above formula, the result is as following:
W=0.5Q*480/（4.18*5）=11.48Q kg

Note:

The above formula is only for reference, different factor should be adopted to suit for different condition.

8. Unit sound levels

Unit Model

Compressor

Model

Sound pressure

level(dB)

Unit Model

Compressor Model

Sound pressure

level(dB)

LSBLG255/MZ

RC-2-M255B

80.7

LSBLG860/MZ

RC-2-M860B

83

LSBLG320/MZ

RC-2-M320B

81

LSBLG970/MZ

2×RC-2-M485B

83.3

LSBLG400/MZ

RC-2-M400B

81.4

LSBLG1060/MZ

RC-2-M485B +

RC-2-M570B

83.5

LSBLG485/MZ

RC-2-M485B

81.7

LSBLG1260/MZ

2×RC-2-M630B

84

LSBLG630/MZ

RC-2-M630B

82.5

LSBLG1490/MZ

RC-2-M630B +

RC-2-M860B

84.6

9. Compressor oil

Refrigeration oil type is subject to the compressor nameplate. The compressor recommended oil level
are as follow:

Unit Model

Compressor Model

Oil level(L)

Unit Model

Compressor Model

Oil level(L)

LSBLG255/MZ

RC-2-M255B

14

LSBLG860/MZ

RC-2-M860B

28

LSBLG320/MZ

RC-2-M320B

14

LSBLG970/MZ

2×RC-2-M485B

2×18

LSBLG400/MZ

RC-2-M400B

15

LSBLG1060/MZ

RC-2-M485B +

RC-2-M570B

18+23

LSBLG485/MZ

RC-2-M485B

18

LSBLG1260/MZ

2×RC-2-M630B

2×23

LSBLG630/MZ

RC-2-M630B

23

LSBLG1490/MZ

RC-2-M630B +

RC-2-M860B

23+28

10. Recommend breaker current

All units has equipped with breaker with user. All refrigerant circuit repairs must be carried out by a
trained, qualified and skilled technician and following local regulations

Midea recommended breaker current for units as follow:

Model

Rated current (A)

Maximal current (A)

Start current (A)

Recommend breaker current

LSBLG255/MZ

92

120

230

171

LSBLG320/MZ

119

148

260

203

LSBLG400/MZ

146

189

292

268

LSBLG485/MZ

171

205

407

310

LSBLG630/MZ

213

277

503

393

LSBLG860/MZ

295

383

785

534

LSBLG970/MZ

341

445

407

620

LSBLG1060/MZ

365

458

443

665

LSBLG1260/MZ

427

554

503

786

LSBLG1490/MZ

509

662

785

927

Note: 970-1490 models are the dual compressor units, because two compressors do not start at the

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

26

same time, so the starting current of 970-1490 models are the single compressor start-up current value.

Note:

(1) Values obtained at standard unit operating conditions: evaporator entering/leaving water
temperature = 12°C/7°C. Condenser entering/leaving water temperature = 30°C/35°C.

(2) For the dual compressor unit, we suggest equipped with breaker for each circuit.

11.Operating Range

Content

Running range

Chilled Leaving Water Temperature

5℃～15℃

Cooling Entering water Temperature

20℃~35℃

Water flow volume

Rating flow volume ±20%

Inlet/outlet water Temp. difference

3.8℃~ 7.1℃

Fouling factor (m2.℃/kW)

0.086

Voltage tolerance

Rating Voltage±10%

Phase tolerance

±2％

Power supply frequency

Rating frequency±2%

Evaporator max working pressure on water side

1.0MPa

Compressor max. start count

4 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

Normal operation ambient temperature

-10℃~45℃

Storage and transport temperature

-15℃～50℃

Applicable altitude range：

No more than 1000m

Operating limits and changes water temperature curve

LSBLG***/MZ evaporator

Minimum

Maximum

Entering temperature at start-up

12°C

35°C

Leaving temperature during operation

5°C

15°C

Entering/leaving temperature difference at full load

3.8°C

7.1°C

LSBLG***/MZ condenser

Minimum

Maximum

Entering temperature at start-up

19°C

35°C

Leaving temperature during operation

25°C

40°C

Entering/leaving temperature difference at full load

3.8°C

7.1°C

Note:

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

27

(1) For low-temperature applications, where the leaving water temperature is below 5°C, freeze protection switch will
work unit stop.

(2) If the temperature leaving the condenser is below 19°C,the unit will stop and warning.
(3) Ambient temperatures: During storage and transport of the LSBLG***/M units. Including by container the minimum

and maximum permissible temperatures is -20°C ~50°C.

Changes water temperature curve in the operation

DX type water-cooled screw chiller (PCB Control) MCAC-CTSM-2014-03

28

12.Capacity table

LSBLG255/MZ

LSBLG320/MZ

Chilled Water

Outlet Temp.

Cooling Water Inlet Temp.(°C)

25.00

26.00

27.00

29.00

30.00

32.00

33.00

35.00

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

(°C)

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

5.00

292.48

58.91

289.33

59.90

286.18

60.95

279.58

63.06

276.13

64.11

269.22

66.48

265.76

67.61

258.83

70.04

6.00

313.85

60.19

310.23

61.19

306.92

62.25

299.85

64.45

296.32

65.52

288.94

67.86

285.39

69.07

277.99

71.54

7.00

336.55

61.47

333.16

62.55

329.45

63.63

321.72

65.85

318.00

67.00

310.31

69.37

306.31

70.59

298.30

73.09

8.00

361.30

62.94

357.47

64.03

353.64

65.06

345.64

67.31

341.47

68.54

333.14

70.94

328.97

72.17

320.39

74.72

9.00 / /

383.14

65.38

378.84

66.56

370.26

68.85

365.97

70.10

357.39

72.53

352.76

73.78

343.83

76.42

10.00

/ / 409.86

66.89

405.45

68.02

396.61

70.41

392.19

71.61

382.53

74.07

377.62

74.69

367.81

78.11

11.00

/ / 437.53

68.29

432.95

69.43

423.46

71.92

418.53

73.14

408.67

75.70

403.73

76.99

393.25

79.71

12.00

/ / 468.23

69.93

463.49

71.08

453.29

73.54

447.82

74.84

437.25

77.44

432.15

78.74

421.19

81.56

13.00

/ / / / 494.29

72.61

483.75

75.17

478.10

76.49

466.79

79.12

461.14

80.51

449.89

83.37

14.00

/ / / / 526.91

74.23

515.69

76.82

509.89

78.09

497.90

80.83

492.08

82.32

479.67

85.22

15.00

/ / / / 561.75

75.93

549.81

78.56

543.83

79.84

531.47

82.62

525.10

84.06

511.96

87.07

Note: The inlet/outlet water temperature difference is 5 ℃.

Chilled Water

Outlet Temp.

Cooling Water Inlet Temp.(°C)

25.00

26.00

27.00

29.00

30.00

32.00

33.00

35.00

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

(°C)

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

5.00

232.70

47.13

230.19

47.92

227.68

48.76

222.43

50.45

219.69

51.29

214.19

53.19

211.44

54.08

205.93

56.04

6.00

249.70

48.15

246.82

48.95

244.18

49.80

238.56

51.56

235.75

52.42

229.88

54.29

227.06

55.25

221.17

57.23

7.00

267.76

49.18

265.06

50.04

262.11

50.90

255.96

52.68

253.00

53.60

246.88

55.49

243.70

56.47

237.32

58.47

8.00

287.45

50.35

284.40

51.22

281.35

52.04

274.99

53.85

271.67

54.84

265.04

56.75

261.73

57.74

254.90

59.77

9.00 / /

304.82

52.30

301.40

53.25

294.58

55.08

291.17

56.08

284.34

58.02

280.66

59.02

273.55

61.14

10.00

/ / 326.08

53.51

322.57

54.42

315.54

56.33

312.02

57.29

304.34

59.25

300.44

59.76

292.63

62.49

11.00

/ / 348.10

54.64

344.46

55.55

336.90

57.54

332.98

58.51

325.14

60.56

321.21

61.59

312.87

63.77

12.00

/ / 372.52

55.94

368.75

56.87

360.64

58.83

356.28

59.87

347.88

61.95

343.81

62.99

335.10

65.25

13.00

/ / / / 393.25

58.09

384.87

60.14

380.37

61.19

371.38

63.30

366.88

64.41

357.93

66.70

14.00

/ / / / 419.21

59.38

410.28

61.46

405.67

62.47

396.12

64.67

391.50

65.85

381.63

68.17

15.00

/ / / / 446.92

60.74

437.43

62.85

432.67

63.87

422.84

66.10

417.77

67.24

407.31

69.66

MCAC-CTSM-2014-03 DX type water-cooled screw chiller (PCB Control)

29

LSBLG400/MZ

Chilled Water

Outlet Temp.

Cooling Water Inlet Temp.(°C)

25.00

26.00

27.00

29.00

30.00

32.00

33.00

35.00

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

(°C)

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

5.00

367.90

74.74

363.94

75.99

359.97

77.32

351.67

80.00

347.33

81.34

338.64

84.35

334.29

85.77

325.58

88.86

6.00

394.78

76.36

390.22

77.63

386.06

78.97

377.17

81.77

372.73

83.13

363.45

86.10

358.98

87.62

349.67

90.76

7.00

423.34

77.98

419.07

79.35

414.40

80.72

404.67

83.55

400.00

85.00

390.33

88.00

385.30

89.55

375.22

92.73

8.00

454.47

79.84

449.65

81.23

444.82

82.53

434.76

85.40

429.53

86.96

419.04

90.00

413.80

91.56

403.00

94.79

9.00

/ / 481.93

82.95

476.53

84.44

465.73

87.35

460.34

88.93

449.55

92.02

443.73

93.60

432.49

96.95

10.00

/ / 515.55

84.86

509.99

86.29

498.88

89.33

493.32

90.85

481.17

93.96

475.00

94.76

462.65

99.10

11.00

/ / 550.35

86.64

544.60

88.09

532.66

91.25

526.46

92.79

514.05

96.04

507.84

97.67

494.65

101.12

12.00

/ / 588.97

88.71

583.01

90.18

570.18

93.29

563.29

94.94

550.00

98.25

543.58

99.90

529.80

103.47

13.00

/ / / / 621.75

92.12

608.49

95.36

601.38

97.03

587.16

100.38

580.05

102.14

565.89

105.77

14.00

/ / / / 662.78

94.17

648.67

97.46

641.38

99.06

626.28

102.55

618.97

104.43

603.36

108.11

15.00

/ / / / 706.60

96.33

691.58

99.67

684.06

101.29

668.52

104.82

660.51

106.64

643.97

110.47

LSBLG485/MZ

Chilled Water

Outlet Temp.

Cooling Water Inlet Temp.(°C)

25.00

26.00

27.00

29.00

30.00

32.00

33.00

35.00

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

Capacity

Power

(°C)

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

kW

5.00

446.08

87.93

441.28

89.40

436.47

90.97

426.40

94.12

421.14

95.69

410.61

99.23

405.33

100.90

394.76

104.54

6.00

478.66

89.84

473.14

91.33

468.09

92.91

457.32

96.20

451.93

97.80

440.68

101.29

435.27

103.09

423.98

106.78

7.00

513.30

91.74

508.12

93.35

502.46

94.96

490.67

98.29

485.00

100.00

473.28

103.53

467.17

105.35

454.95

109.09

8.00

551.05

93.93

545.20

95.57

539.35

97.10

527.15

100.47

520.80

102.31

508.09

105.88

501.73

107.72

488.64

111.52

9.00

/ / 584.34

97.58

577.79

99.34

564.70

102.76

558.16

104.63

545.07

108.25

538.02

110.12

524.39

114.06

10.00

/ / 625.10

99.84

618.37

101.52

604.89

105.09

598.15

106.88

583.42

110.55

575.93

111.48

560.96

116.59

11.00

/ / 667.30

101.93

660.32

103.63

645.84

107.35

638.33

109.16

623.28

112.99

615.75

114.90

599.76

118.97

12.00

/ / 714.12

104.37

706.90

106.09

691.34

109.76

682.99

111.70

666.88

115.58

659.09

117.52

642.38

121.73

13.00

/ / / / 753.87

108.37

737.79

112.19

729.18

114.16

711.93

118.09

703.31

120.17

686.15

124.44

14.00

/ / / / 803.62

110.79

786.51

114.66

777.67

116.55

759.37

120.65

750.51

122.86

731.58

127.19

15.00

/ / / / 856.75

113.33

838.54

117.25

829.43

119.16

810.58

123.32

800.86

125.46

780.81

129.96

Note: The inlet/outlet water temperature difference is 5 ℃.