Midea MWSC340A-FB3 User manual

Midea R134a 50Hz l
Flooded type water cooled
screw chiller (PCB Control)
Applicable Model:
Midea reserves the right to discontinue, or change specification or designs at any time without notices and
without incurring obligations.
DM15-01.01.18en
MWSC340A-FB3
MWSC440A-FB3
MWSC540A-FB3
MWSC690A-FB3
MWSC805A-FB3
MWSC890A-FB3
MWSC1080A-FB3
MWSC1200A-FB3
MWSC1385A-FB3
MWSC1620A-FB3
MWSC1780A-FB3
Библиотека СОК 

Flooded 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............................................................................................................................. 13
4. Outline dimension...................................................................................................................... 15
5. Refrigeration system.................................................................................................................. 16
6. Major system components......................................................................................................... 17
7. Water flow.................................................................................................................................. 21
8. Operating range......................................................................................................................... 24
9. Capacity table............................................................................................................................ 25
10. Accessories........................................................................................................................ 31
III. Control ...........................................................................................................32
1. Control flow chart....................................................................................................................... 32
2. Energy adjustment..................................................................................................................... 33
3. Start/stop process...................................................................................................................... 34
4. Sensors...................................................................................................................................... 35
5. Parts control............................................................................................................................... 36
6. Operation part............................................................................................................................ 44
7. Safety protection........................................................................................................................ 57
IV. Electrical control...........................................................................................59
1. Electrical data ............................................................................................................................ 59
2. Electrical components introduction............................................................................................ 60
3. Electrical parts parameter setting.............................................................................................. 62
4. Field wiring.................................................................................................................................64
5. Wiring Diagrams........................................................................................................................ 67
V. Installation.....................................................................................................76
1. Unit installation........................................................................................................................... 76
2. Water pipeline system installation ............................................................................................. 79
3. Wiring installation....................................................................................................................... 85
VI. Commissioning.............................................................................................87
1. Pre start-up................................................................................................................................ 87
2. Start-up...................................................................................................................................... 91
VII. Maintenance ..................................................................................................93
1. Daily maintenance..................................................................................................................... 93
2. Maintenace ................................................................................................................................ 97
VIII. Troubleshooting..........................................................................................104
1. Protection items.......................................................................................................................104
2. Troubleshooting.......................................................................................................................107
IX. Appendix 1...................................................................................................110
Manufacture reserves the right to discontinue, or change at any time, specifications or designs without notices and witho
ut incurring obligations.
Climate solution for green environment
Flooded Type
Water cooled screw chiller
Technical service manual
LSBLG365~LSBLG1500/MCFN

Flooded type water cooled screw chiller (PCB Control)
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
(1) 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.
(2) 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.
(3) 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.
(4) 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:
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.
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. 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 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.

Flooded type water cooled screw chiller (PCB Control)
3
2. Maintenance safety considerations
2.1 Engineers safety consideration
(1) 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.
(2) 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: During any handling, maintenance and service operations the engineers working on the unit
must be equipped with safety gloves, glasses, shoes and protective clothing.
(1) Never work on a unit that is still energized.
(2) 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.
(3) If any maintenance operations are carried out on the unit, lock the power supply circuit ahead of the
machine.
(4) If the work is interrupted, always ensure that all circuits are still deenergized 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: R134a
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.
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

Flooded type water cooled screw chiller (PCB Control)
4
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 ensure 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 R134a charge, as indicated on the
unit name plate. Certain parts of the circuit can be isolated. Only charge liquid refrigerant R134a 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 (R134a) 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 weld or flame cut the refrigerant lines or any refrigerant circuit component until all refrigerant
(liquid and vapor) has been removed from chiller. Traces of vapor 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.
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.

Flooded type water cooled screw chiller (PCB Control)
5
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 hydronic 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.

Flooded type water cooled screw chiller (PCB Control)
6
II. Product
1. General Information
1）Product Line Up
Series
Model
Power Supply
Cooling Capacity
(kW)
Quantity of
Compressor
Single head
MWSC340A-FB3
380V/3Ph/50Hz
340
1
MWSC440A-FB3
380V/3Ph/50Hz
440
1
MWSC540A-FB3
380V/3Ph/50Hz
540
1
MWSC690A-FB3
380V/3Ph/50Hz
690
1
Dual head
MWSC805A-FB3
380V/3Ph/50Hz
805
1
MWSC890A-FB3
380V/3Ph/50Hz
890
1
MWSC1080A-FB3
380V/3Ph/50Hz
1080
2
MWSC1200A-FB3
380V/3Ph/50Hz
1200
2
MWSC1385A-FB3
380V/3Ph/50Hz
1385
2
MWSC1620A-FB3
380V/3Ph/50Hz
1620
2
MWSC1780A-FB3
380V/3Ph/50Hz
1780
2

Flooded type water cooled screw chiller (PCB Control)
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3). External appearance
Single head(MWSC340A-FB3~ MWSC890A-FB3)
Dual head(MWSC1080A-FB3~ MWSC1780A-FB3)

Flooded type water cooled screw chiller (PCB Control)
8
R134a
R134a
2. Features
High efficiency
High efficiency inner grooved copper pipe enhances the heat-exchange process,
improves heat exchange efficiency and makes the evaporator more compact to
save installation space.
Significantly improve the evaporating temperature and reduce heat transferring
temperature difference which directly improves heat-exchange efficiency, provide
most cost effective & reliable solutions to all valuable customers.
Supreme efficiency in partial load.
Green chiller
R134a environmental-friendly refrigerant
Refrigerant of the Chlorine-free HFC with zero ODP (Ozone Depletion Potential).
Very low GWP (Global Warming Potential).
High reliability and excellent serviceability
Advanced twin-rotor screw compressor
High efficiency heat exchange technology
High efficiency shell and tube heat exchanger, 2 path, straight water pipe, easy to clean. End cover can
be exchanged to meet customer’s requirement for condenser.
Capacity adjustable valve
Built-in oil separator
Motor direct drive
Four stage capacity adjustable or
stepless adjustable. Exhaust cavity with check valve, it can avoid compressor to reversal
cause of stopping for long time.
Patent type line design, high
volumetric efficiency, smooth
operation.
Cool motor with refrigerant, no
heat send out in room.
Semi-hermetic compressor,
moveable bolts, easy to
maintain.
High precision filter, the oil
separation efficiency up to
99.5%.
High mechanical efficiency, low
speed of compressor, low
noise.
Refrigerant discharge
Twin screw rotor
Hermetic motor
Semi- hermetic structure
Gas refrigerant Chilled
water outlet
Chilled
water inlet
EXV Liquid
refrigerant Tube
Orifice
Filter
Cooling
water inlet
Cooling
water outlet
Gas refrigerant inlet
Liquid refrigerant outlet
Filter

Flooded type water cooled screw chiller (PCB Control)
9
Flooded evaporator makes cleaning inside of pipes possible, and guarantees high reliability.
Discharge cut-off valve and liquid line angle valve for simplified maintenance.
Simplified field wiring for easy installation.
Optimized & user-friendly operating Interface
Midea chiller adopts Midea Microprocessor which provides
advanced algorithm and reliable control.
Graphical display of the operating state, operation scheduling.
malfunction inquiry, help menu for easy trouble shooting and other
user-oriented functions.
Compressor bearing
High-precision large-sized axial and radial bearings are selected to support the male and female
rotors for long lasting life. With effective lubrication system, the bearing service life can be further
extended. While the compressor is running, lubricant is injected into all bearings due to pressure
difference.
SKF brand industry use bearing guarantees 60,000h continuous working
Advanced twin-rotor screw compressor
Midea® Screw Chiller equipped with the 3rd generation industrial Semi-hermetic Screw compressor
that has the latest advanced 5-6 asymmetry dentiform rotors. The rotors are processed by
high-precision CNC and each part is well-proportioned and none-gap matching, which minimize the
friction resistance and clearance loss, guarantee quiet running and good duration.

Flooded type water cooled screw chiller (PCB Control)
10
High-precision machining and measurement make rotor clearance reach μm-class, so it reduces the
leakage between high and low pressure. Under continuous operation, the rotors still keep their best
clearance and achieve highest efficiency.
Semi-hermetic compressor with low running noise and well cooled down by refrigerant, low running
temperature, no leakage potential compared with open compressor.
Patented motor-cooling design in ducts of refrigerant flow encompassing stator provides best
dissipation of heat and no requirement for computer room AC.
To reach high operation efficiency, the casing is manufactured by precise machining centers and
inspected by a coordinate measuring machine to make sure that the requested precision and quality
can be retained in the compressor.
Three stages oil separation
The built-in oil separator utilizes three-stage filter mechanism with high-density filter element to
achieve optimal oil separation effect and its efficiency is higher than 99.7%.Two oil separators
cooperate together make the best oil separating effect.
Detachable demister for cleaning.
Oil supplied by pressure difference and no need of oil pump.
Dual compressors (Min. 1080 ~ Max.1780kW)

Flooded type water cooled screw chiller (PCB Control)
11
Large cooling capacity chillers have two truly independent refrigerant circuits, compact outline and
superior partial load efficiency. Besides, when one of the compressors breaks down, the other one
can work independently. So the chiller can provide much higher reliability and minimize the loss of
user.
Flooded-type evaporator
Evaporator is flooded type designed for 1MPa working pressure on the chillled water side (Higher
pressure vessels can be customized). Replaceable integral finned copper tubes are mechanically
bonded to steel tube sheets. The evaporator has been tested under
extreme conditions. The 20MM thickness insulation covers all low
temperature surfaces, including the evaporator, water boxes, oil
return lines, chilled water flow switch piping, etc.
Midea heat exchangers are designed by professional design
software and pass rigorous tests. Double-grooved holes at tube
support for tube expansion are designed to prevent leakage and
increase the durability of heat exchanger.
Condenser
Midea condenser has a specially designed baffle, in the entrance of condenser, to prevent direct
impingement of high-velocity refrigerant gas on tube surface and thus eliminate the related vibration
and noise. It has been tested under extreme conditions. Water side working pressure is designed
for 1.0Mpa (Higher pressure vessels can be customized).
Throttling device
Orifice baffle without moving parts can guarantee high reliability and it
cooperates with EXV（Danfoss）to throttle the high-pressure liquid
refrigerant from condenser to evaporator.EXV which is controlled by
EVD module provides high-precision adjustment and perfectly
matches the compressor load，both
full load and partial load.
Advanced oil system
As the diagram shown, the low
temperature and low pressure gas
enters the compressor through
suction port. Then refrigerant gas that
entered the compressor is
compressed to a high temperature
and high pressure gas and enters the
condenser to release heat to cooling
water. The condensed liquid passes
the throttling device, becomes the

Flooded type water cooled screw chiller (PCB Control)
12
mixed state and enters the lower part of the evaporator. It is then spread into a wider surface by
distributor. Finally the distributed refrigerant evaporates by taking the heat from the chilled water inside
the evaporator tube and repeats the cycle.
Lubrication cycle
Three stages oil separation ensure the excellent compressor lubricant. One is integrated inside the
compressor and the other is built-in oil separator located inside of the condenser. The refrigerant and oil
mixture gets separated in the internal oil separator for the first time and then to the condenser oil
separator of which the separating efficiency can reach 99%. Oil will return to compressor through the oil
return pipe by pressure difference. Small amount of oil which remains in the evaporator will be sucked up
by the Venturi tube and goes back to compressor after gas evaporating. This is the third stages oil
separation. These three oil return circuits can guarantee reliable oil return efficiency.

Flooded type water cooled screw chiller (PCB Control)
13
3. Specifications
Single head
MWSC_A-FB3
340
440
540
690
805
890
Cooling capacity
kW
340
440
540
690
805
890
Power input
kW
60
77
94
120
140
155
EER
kW/kW
5.66
5.71
5.74
5.75
5.75
5.74
Semi-hermetic screw compressor
Circuit A
Quantity
1
1
1
1
1
1
Circuit B
Quantity
--
--
--
--
--
--
Oil recharge
Circuit A
L
18
20
23
28
40
40
Circuit B
L
--
--
--
--
--
--
Refrigerant
Type
R134a
Circuit A
kg
130
145
160
200
230
250
Circuit B
kg
--
--
--
--
--
--
Control Type
EXV+Orifice
Evaporator
Type
Shell and tube flooded
Water content
L
150
170
190
210
240
270
Water flow
m³/h
58
76
93
119
138
153
Pressure drop
kPa
55
49
53
46
39
39
Max. pressure
kPa
1000
1000
1000
1000
1000
1000
Connection type
Victaulic coupling
Water inlet/outlet pipe dim.
mm
150
150
150
200
200
200
Condenser
Type
Shell and tube
Water content
L
150
170
190
210
240
270
Water flow
m³/h
73
95
116
148
173
191
Pressure drop
kPa
75
70
77
66
56
56
Max. pressure
kPa
1000
1000
1000
1000
1000
1000
Connection type
Victaulic coupling
Water inlet/outlet pipe dim.
mm
150
150
150
200
200
200
Unit length
mm
3550
3550
3550
3600
3600
3600
Unit width
mm
1220
1220
1220
1420
1440
1440
Unit height
mm
1730
1800
1900
2000
2020
2020
Shipping weight
kg
2500
2580
2950
3550
4050
4150
Running weight
kg
2700
2820
3220
3870
4420
4550
Safety protection device
The following safety devices are equipped as standard.
High pressure protection(High pressure switch & high pressure sensor)
Low pressure protection(Low pressure switch & low pressure sensor)
Compressor thermal protection
High discharge temperature on the compressor
Phase monitor; Star/Delta transition failed
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 following conditions: Chilled water inlet/outlet temperature 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 0.086m2•℃/kW (0.0005ft2 F.hr/Btu).

Flooded type water cooled screw chiller (PCB Control)
14
Dual head
MWSC_A-FB3
1080
1200
1385
1620
1780
Cooling capacity
kW
1080
1200
1385
1620
1780
Power input
kW
186
206
238
278
306
EER
kW/kW
5.8
5.82
5.81
5.82
5.81
Semi-hermetic screw compressor
Circuit A
Quantity
1
1
1
1
1
Circuit B
Quantity
1
1
1
1
1
Oil recharge
Circuit A
L
23
28
28
40
40
Circuit B
L
23
28
28
40
40
Refrigerant
Type
R134a
Circuit A
kg
170
180
190
210
220
Circuit B
kg
170
180
190
210
220
Control type
EXV+Orifice
Evaporator
Type
Shell and tube flooded
Water content
L
350
400
460
520
580
Water flow
m³/h
186
206
238
279
306
Pressure drop
kPa
78
79
79
75
76
Max. pressure
kPa
1000
1000
1000
1000
1000
Connection type
Victaulic coupling
Water inlet/outlet pipe dim.
mm
200
200
200
200
200
Condenser
Type
Shell and tube
Water content
L
350
400
460
520
560
Water flow
m³/h
232
258
298
348
383
Pressure drop
kPa
88
87
87
85
86
Max. pressure
kPa
1000
1000
1000
1000
1000
Connection type
Victaulic coupling
Water inlet/outlet pipe dim.
mm
200
200
200
200
200
Unit length
mm
4600
4600
4600
4800
4800
Unit width
mm
1520
1520
1520
1620
1620
Unit height
mm
2035
2035
2035
2250
2250
Shipping weight
kg
6700
6900
7150
8350
8450
Running weight
kg
7250
7490
7820
9200
9350
Safety protection device
The following safety devices are equipped as standard.
High pressure protection(High pressure switch & high pressure sensor)
Low pressure protection(Low pressure switch & low pressure sensor)
Compressor thermal protection
High discharge temperature on the compressor
Phase monitor; Star/Delta transition failed
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 following conditions: Chilled water inlet/outlet temperature 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 0.086m2•℃/kW (0.0005ft2 F.hr/Btu).

Flooded type water cooled screw chiller (PCB Control)
15
4. Outline dimension
Single head (MWSC340~890A-FB3)
Unit: mm
Model
Ａ
Ｂ
Ｃ
Ｄ
Ｅ
Ｆ
Ｇ
Ｈ
J
K
L
Water
inlet/outlet Dim.
MWSC340A-FB3
3550
1220
1730
2850
1100
411
260
250
850
260
541
DN150
MWSC440A-FB3
3550
1220
1800
2850
1100
411
260
250
850
260
541
DN150
MWSC540A-FB3
3550
1220
1900
2850
1100
411
260
250
850
260
541
DN150
MWSC690A-FB3
3600
1420
2000
2850
1300
451
280
300
1000
280
591
DN200
MWSC805A-FB3
3600
1440
2020
2850
1300
451
280
300
1000
280
591
DN200
MWSC890A-FB3
3600
1440
2020
2850
1300
451
280
300
1000
280
591
DN200
Dual heads(MWSC1080~1780A-FB3)
Unit: mm
Model
Ａ
Ｂ
Ｃ
Ｄ
Ｅ
Ｆ
Ｇ
Ｈ
J
K
L
Water inlet/outlet Dim.
MWSC1080A-FB3
4600
1520
2035
3850
1400
443
350
325
1075
350
618
DN200
MWSC1200A-FB3
4600
1520
2035
3850
1400
443
350
325
1075
350
618
DN200
MWSC1385A-FB3
4600
1520
2035
3850
1400
443
350
325
1075
350
618
DN200
MWSC1620A-FB3
4800
1620
2250
3850
1500
468
350
350
1150
350
643
DN200
MWSC1780A-FB3
4800
1620
2250
3850
1500
468
350
350
1150
350
643
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.
Cooling
water inlet
Chilled
water inlet
Cooling
water outlet Chilled
water outlet
B
E
J
K
H
F
LC
G
Cooling
water inlet
Chilled
water inlet
Cooling
water outlet Chilled
water outlet
B
E
J
K
H
F
LC
G
A
D
D
A
D

Flooded type water cooled screw chiller (PCB Control)
16
5. Refrigeration system
For single head unit( MWSC340~890A-FB3)
For dual heads unit (MWSC1080~1780A-FB3)

Flooded type water cooled screw chiller (PCB Control)
17
6. Major system components
6.1 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.
MWSC_A-FB3 Series units are provided with a high efficiency oil separator to maximize oil extraction.
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).
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 andAmerican 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.

Flooded type water cooled screw chiller (PCB Control)
18
Lubricant:
The lubricant is supplied automatically by pressure difference inside the compressor. It is
unnecessary to add an extra lubricant pump.
The compressor is approved for use with the following lubricant:
HBR-B04 for R134a unit
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.
Oil filter
The screw compressor has an independent oil filter.

Flooded type water cooled screw chiller (PCB Control)
19
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,
annex C.
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
The unit is equipped with safety valves. And ball valve is connecting safety valve to condenser
(evaporator). The ball valve maintain full-state, it is closed only when safety valve is opening or replaced.