Midea LSBLG320/MZ Operating manual

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Commercial Air Conditioner Division
Midea Group
Address: Midea Headquarters Building, 6 Midea Avenue, Beijiao, Shunde, Foshan,
Guangdong, China
Postal code: 528311
Tel: [phone] Fax: [phone]
cac.midea.com global.midea.com
Note: The data in this book may be changed without notice for further improvement on
quality and performance.
LSBLG***/MZ
Model:
Technical Service Manual
Water-cooled
Screw Chiller

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

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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.

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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
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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
(kW)
Design sequence code
C: R134a; omit for R22
Z
Z: Factory code

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3). External Appearance
LSBLG255/MZ~ LSBLG860/MZ
LSBLG970/MZ~ LSBLG1490/MZ

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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.

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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.