LG RCAW Operation & Maintenance Manual

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Page 1

Operation & Maintenance Manual

MODELS: RCAW - Compact (50Hz)

website http://www.lgservice.com

IMPORTANT

• Please read this Operation & Maintenance Manual completely before Operating & Maintenance the product.

• Operating & Maintenance must be performed in accordance with the national wiring standards by authorized personnel only.

• Please retain this Operating & Maintenance for future reference after reading it thoroughly.

R134a

Chiller Air-cooled Screw

Page 2

2 Chiller Air-cooled Screw

SAFETY CONSIDERATIONS

Warning...................................................................................................................................3

Caution....................................................................................................................................7

GENERAL

Manipulation of HMI Unit.......................................................................................................11

CONTROLS

PLC and HMI Unit.................................................................................................................21

Machine on/off control...........................................................................................................30

START-UP

Pre Start-up ..........................................................................................................................31

Start-up Procedure................................................................................................................32

Operation Limits....................................................................................................................34

OPERATION

Sequence of Operation.........................................................................................................37

Sensors.................................................................................................................................42

SERVICE

Cycle Components................................................................................................................43

Control System .....................................................................................................................56

Maintenance .........................................................................................................................67

TROUBLE SHOOTING............................................................................................................68

APPENDIX

Wiring Diagram .....................................................................................................................76

Cycle Diagram.......................................................................................................................77

Check List .............................................................................................................................78

Air cooled Screw Operation & Maintenance Manual

TABLE OF CONTENTS

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Safety Considerations

Operation & Maintenance Manual 3

Installing, starting up, and servicing this equipment can be hazardous due to system pressures, electrical components, and equipment location (roof, elevated structures, etc). Only trained, qualified installers and service technicians should install, start up, and service this equipment. When working on this equipment, observe precautions in the literature, and on tags, stickers, and labels attached to the equipment, and any other safety precautions that apply. Follow all safety codes. Wear safety glasses and work gloves. Use care in handling, rigging, and setting this equipment, and in handling all electrical components.

To prevent injury to the user or other people and property damage, the following instructions must be followed.

■ Incorrect operation due to ignoring Instructions in the manual will cause harm or damage. The seriousness is classified by the following indications.

■ We do not have any responsibility for any failure caused by careless management and natural disaster, and power cord failure regardless of warranty period.

■ The content in the manual could be changed for the improvement of product without notice.

■ Meanings of symbols used in this manual are as shown below.

This symbol indicates the possibility of death or serious injury. This symbol indicates the possibility of injury or damage to properties only.

Be sure not to do.

Be sure to follow the instruction.

Have all electric work done by a licensed electrician according to "Electric Facility Engineering Standard" and "Interior Wire Regulations" and the instructions given in this manual and always use a special circuit.

• If the power source capacity is inadequate or electric work is performed improperly, electric shock or fire may result.

Ask the dealer or an authorized technician to install the chiller.

• Improper installation by the user may result in water leakage, electric shock, or fire.

SAFETY CONSIDERATIONS

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Safety Considerations

4 Chiller Air-cooled Screw

For re-installation of the installed product, always contact a dealer or an Authorized Service Center.

•

There is risk of fire, electric shock, explosion, or injury.

Do not install, remove, or re-install the unit by yourself (customer).

•

There is risk of fire, electric shock, explosion, or injury.

Do not store or use flammable gas or combustibles near the chiller.

• There is risk of fire or failure of product.

Use the correctly rated breaker or fuse.

• There is risk of fire or electric shock.

Do not install the product on a defective installation stand.

• It may cause injury, accident, or damage to the product.

When installing and moving the chiller to another site, do not charge it with a different refrigerant from the refrigerant specified on the unit.

• If a different refrigerant or air is mixed with the original refrigerant, the refrigerant cycle may malfunction and the unit may be damaged.

Do not reconstruct to change the settings of the protection devices.

• If the pressure switch, thermal switch, or other protection device is shorted and operated forcibly, or parts other than those specified by LGE are used, fire or explosion may result.

Ventilate before operating chiller when gas leaked out.

• It may cause explosion, fire, and burn.

Securely install the cover of control box and the panel.

• If the cover and panel are not installed securely, dust or water may enter the air-cooled unit and fire or electric shock may result.

If the chiller is installed in a small room, measures must be taken to prevent the refrigerant concentration from exceeding the safety limit when the refrigerant leaks.

• Consult the dealer regarding the appropriate measures to prevent the safety limit from being exceeded. Should the refrigerant leak and cause the safety limit to be exceeded, harzards due to lack of oxygen in the room could result.

Always ground the product.

• There is risk of fire or electric shock.

Always intstall dedicated circuit and breaker.

• Improper wiring or installation may cause fire or electric shock.

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Safety Considerations

Operation & Maintenance Manual 5

Do not damage or use an unspecified power cord.

• There is risk of fire, electric shock, explosion, or injury.

Use a dedicated outlet for this appliance.

• There is risk of fire or electrical shock.

Be cautious that water could not enter the product.

•

There is risk of fire, electric shock, or product damage.

Do not touch the power switch with wet hands.

•

There is risk of fire, electric shock, explosion, or injury.

When the product is soaked (flooded or submerged), contact an Authorized Service Center.

• There is risk of fire or electric shock.

Take care to ensure that nobody could step on or fall onto the air-cooled unit.

• This could result in personal injury and product damage.

Be careful of the rotating part.

• Be careful not to put your finger or a stick in the rotating part of the fan or pump.

• Do not operate the fan with the protective net removed. It can cause body injury.

Use of undesignated refrigerant and oil is prohibited.

• Do not use undesignated refrigerant, freezer oil and brine.

• It can have a critical effect on the compressor and component defects.

• If you would like to use a substitute for the refrigerant, please contact the manufacturer.

Redesigning the control box is prohibited.

• Lock the control box with possible locking device and if you need to open the control box inevitably, turn off the main power first.

•

Do not touch the wiring or parts within the control box.

• It can cause electric shock, fire or defects.

Be careful of leakage.

•

If you find a leakage in the connected part such as pump, piping etc., immediately stop the operation.

• It can cause electric shock, leakage or defects.

Follow the permitted pressure level.

• Follow the regulated pressure for cold water, cooling water, refrigerant etc.

• It can cause electricity leakage or burn/frostbite eruption or leakage.

Be cautious of fire, earthquake and lightning.

• If there is natural disaster such as fire or earthquake, or risk of lightning, immediately stop operating the unit.

• If you continue to operate the unit, it can cause a fire or electric shock.

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Safety Considerations

6 Chiller Air-cooled Screw

Changing the set value is prohibited.

• Do not change the set value of the safety device.

• If you operate the product with incorrectly set values, it can cause defect, fire or explosion.

• When you change the control setting value, please consult with the specialized expert.

Electric shock prevention.

• When installing the freezer, always ground the wire.

• It can cause electric shock.

Follow all safety codes.

• When working on this equipment, observe precautions in the literature, and on tags, stickers, and labels attached to the equipment, and any other safety precautions that apply.

Wear safety equipment.

• Wear safety glasses and work gloves.

•

Use care in handling, rigging, and setting this equipment, and in handling all electrical components.

Shut off all power to this equipment during installation and service.

•

Electrical shock can cause personal injury and death.

• There may be more than one disconnect switch. Tag all disconnect locations to alert others not to restore power until work is completed.

Always run fluid through heat exchangers when adding or removing refrigerant charge.

•

It prevent potential damage to heat exchanger tubes.

• Use appropriate brine solutions in cooler fluid loops to prevent the freezing of heat exchangers when the equipment is exposed to temperatures below 32°F(0°C).

Do not attempt to unbraze factory joints when servicing this equipment. Cut lines with a tubing cutter as required when performing service.

• Compressor oil is flammable and there is no way to detect how much oil may be in any of the refrigerant lines.

• Use a pan to catch any oil that may come out of the lines and as a gage for how much oil to add to system.

Do not re-use compressor oil.

• It may cause damage to the product.

Do not vent refrigerant relief valves within a building.

• Outlet from relief valves must be vented outdoors in accordance with the latest edition of ANSI/ASHRAE (American National Standards Institute/American Society of Heating, Refrigeration and Air Conditioning Engineers) 15 (Safety Code for Mechanical Refrigeration).

• The accumulation of refrigerant in an enclosed space can displace oxygen and cause asphyxiation.

• Provide adequate ventilation in enclosed or low overhead areas. Inhalation of high concentrations of vapor is harmful and may cause heart irregularities, unconsciousness or death. Misuse can be fatal. Vapor is heavier than air and reduces the amount of oxygen available for breathing. Refrigerant causes eye and skin irritation.

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Safety Considerations

Operation & Maintenance Manual 7

Do not leave refrigerant system open to air any longer than necessary.

• Seal circuits being serviced and charge with dry nitrogen to prevent oil contamination when timely repairs cannot be completed.

Always check for gas (refrigerant) leakage after installation or repair of product.

• Low refrigerant levels may cause failure of product.

Do not install the product where the noise or hot air from the air-cooled unit could damage the neighborhoods.

• It may cause a problem for your neighbors.

Keep level even when installing the product.

• To avoid vibration or water leakage.

Do not install the unit where combustible gas may leak.

• If the gas leaks and accumulates around the unit, an explosion may result.

Use power cables of sufficient current carrying capacity and rating.

• Cables that are too small may leak, generate heat, and cause a fire.

Do not use the product for special purposes, such as preserving foods, works of art, etc. It is a consumer chiller, not a precision refrigeration system.

• There is risk of damage or loss of property.

Keep the unit away from children.

• It can cause the injury, such as cutting the finger. Also the damaged fin may result in degradation of capacity.

When installing the unit in a hospital, communication station, or similar place, provide sufficient protection against noise.

•

The inverter equipment, private power generator, highfrequency medical equipment, or radio communication equipment may cause the chiller to operate erroneously, or fail to operate. On the other hand, the chiller may affect such equipment by creating noise that disturbs medical treatment or image broadcasting.

Do not install the product where it is exposed to sea wind (salt spray) directly.

• It may cause corrosion on the product. Corrosion, could cause product malfunction or inefficient operation.

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Safety Considerations

8 Chiller Air-cooled Screw

Do not use the chiller in special environments.

• Oil, steam, sulfuric smoke, etc. can significantly reduce the performance of the chiller or damage its parts.

Make the connections securely so that the outside force of the cable may not be applied to the terminals.

• Inadequate connection and fastening may generate heat and cause a fire.

Be sure the installation area does not deteriorate with age.

• If the base collapses, the chiller could fall with it, causing property damage, product failure, or personal injury.

Be very careful about product transportation.

•

When transporting the chiller, always consult with the specialized expert. When transporting the chiller, make sure to comply with the method regulated in the manual. If not, it can cause overturn, fall etc.

Safely dispose of the packing materials.

•

Packing materials, such as nails and other metal or wooden parts, may cause stabs or other injuries.

•

Tear apart and throw away plastic packaging bags so that children may not play with them. If children play with a plastic bag which was not torn apart, they face the risk of suffocation.

Turn on the power at least 12 hours before starting operation.

• Starting operation immediately after turning on the main power switch can result in severe damage to internal parts. Keep the power switch turned on during the operational season.

Do not touch any of the refrigerant piping during and after operation.

• It can cause a burn or frostbite.

Do not operate the chiller with the panels or guards removed.

• Rotating, hot, or high-voltage parts can cause injuries.

Do not directly turn off the main power switch after stopping operation.

• Otherwise it may result in oil supply shortage or other problems.

Use a firm stool or ladder when cleaning or maintaining the chiller.

• Be careful and avoid personal injury.

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Safety Considerations

Operation & Maintenance Manual 9

Be careful of disposal.

• When disposing the device, request to the specialized expert.

Be careful of high voltage.

•

Install separate wiring for the power and always install and use dedicated power supply and circuit breaker.

• It can cause electric shock or fire.

Be careful of high temperature.

• Because the machine part can be hot, do not

touch it with any part of your body.

• It can cause burns.

Be careful of restarting.

• When the safety device of the product operates, resolve the cause before re-operating.

•

If you repeat this arbitrarily, it can cause fire and defect.

Be careful of device installation.

• Be careful of the clearance of the device during the installation and make sure there are no surrounding obstacles for the air cooling type and that it is well ventilated.

Be careful of sound or odor.

• If you hear a weird sound or smell weird odor, immediately stop operating the unit and contact the service center.

• It can cause fire, explosion and injury.

Check.

• Execute the periodic check. If an issue is found, stop operating the unit and contact the service center.

•

Insufficient check can cause fire, explosion and defect.

Use appropriate tools.

• Use appropriate tools used for the repair and make sure to calibrate the measuring devices precisely before use.

•

If you use inappropriate tools etc, it can cause an accident.

Be careful of air cooling type heat exchanger.

• Because the condenser of the air cooling type device is sharp, do not touch the condenser.

• Protective net must always be kept installed.

• It can cause an injury.

It can cause an injury.

• Check the safety label of the safety device.

• Follow upper precautions and labels. If not, it can cause injury or damage such as a fire etc.

• To prevent the generation of condensed water, the connecting pipe to the evaporator, as well as the evaporator itself, must be insulated.

Do not use jumpers or other tools to short out components, or to bypass or otherwise depart from recommended procedures.

• Any short-to-ground of the control board or accompanying wiring may destroy the electronic modules or electrical components.

Do not attempt to bypass or alter any of the factory wiring.

• Any compressor operation in the reverse direction will result in a compressor failure that will require compressor replacement.

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Safety Considerations

10 Chiller Air-cooled Screw

Consult a water treatment specialist for proper treatment procedures.

• Hard scale may require chemical treatment for its prevention or removal

Water must be within design flow limits, clean and treated.

•

This make it possible to ensure proper machine performance and reduce the potential of tubing damage due to corrosion, scaling, erosion, and algae.

• LG assumes no responsibility for chiller or condenser damage resulting from untreated or improperly treated water.

Rig unit from the top heat exchanger only.

• Rigging from the bottom heat exchanger will cause the unit to be lifted unsafely.

• Personal injury or damage to the unit may occur

Welding is not recommended in the cooler heads or nozzles.

• In the event that welding must be performed, remove the chilled water flow switch and entering and leaving fluid thermistors before welding.

• Reinstall flow switch and thermistors after welding is complete. Failure to remove these devices may cause component damage.

Harsh chemical, household bleach or acid cleaners should not be used to clean outdoor or indoors coils of any kind.

• These cleaners can be very difficult to rinse out of the coil and can accelerate corrosion at the fin/tube interface where dissimilar materials are in contact. If there is dirt below the surface of the coil, use the Environmentally Sound Coil Cleaner.

Do not use high-pressure water or air to clean coils.

• It may cause fin damage

•

High Velocity Water or Compressed Air should never be used to clean a coil. The force of the water or air jet will bend the fin edges and increase airside pressure drop. Reduced unit performance or nuisance unit shutdown may occur.

Do not overcharge system.

• Overcharging results in higher discharge pressure with higher cooling fluid consumption, possible compressor damage and higher power consumption.

Do not add oil at any other location.

• It may cause improper unit operation

Compressor oil is pressurized.

• Use proper safety precautions when relieving pressure.

Turn controller power off before servicing controls.

• This ensures safety and prevents damage to controller.

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General

Operation & Maintenance Manual 11

GENERAL

This manual is composed of information on control, operation, start-up, service and troubleshooting of RCAW Air Cooled Chiller.

■ Manipulation of HMI(Human Machine Interface) Unit

If it is strongly recommended that the user NOT change any programing without consulting LGE service personnel. Unit damage may occur from improper programming.

The menu structure of the HMI unit is shown in the below. As you can see, there are 7 menu items for user interface. Moving among menu items are accomplished by the manipulation of the arrow keys . To see the detail information of the each menu item, press the arrow key . To start up the chiller start button must be pressed for more than 3 seconds. Similarly, to shut down the chiller, stop button must be pressed for more than 3 seconds.

Main Menu

System Setting User Setting Content

System Setting

Main Display Par. Setting Content

Par. Setting

System Setting Delay Setting Content

Alarm Display

Delay Setting User Setting Content

Delay Setting

Par. Setting Alarm Display Content

Flooded Air-Cool Screw Chiller

SYS 2.71 PG 14.01

I/O Display

User Setting Alarm Display Content

User Setting

I/O Display Main Display Content

Fig. 1

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General

12 Chiller Air-cooled Screw

Main Menu

The main menu is composed of 4 screen cuts. Moving among them is accomplished by the manipulation of the arrow keys . The main menu shows configured control parameter of the PLC, temperature inputs, and accumulated compressor running hour and current running capacity

In the below main menu, hand/auto mode is configured to be auto control, control mode is configured to be local control. These two items are configurable through user setting menu. The auto control represents the operation mode using scheduling program without key manipulation or remote signal. Contrarily, hand control represents the operation mode using key manipulation or remote signal.

All temperature readings are displayed on the main menu. The temperature readings include chilled water entering temperature (CHW In Temp), outdoor air temperature (Ambient Temp), compressor exhaust temperature (Exhaust Temp), chilled water leaving temperature (CHW Out Temp), and condenser refrigerant leaving temperature (Condensate Temp).

Compressor running hours(Comp Running Hrs) means accumulated running hours of the compressor. This value can be initialized by operator if needed. For example, if we replace the compressor with new one, the value must be initialized.

The running capacity can be 0%, 25%, 50%, 75%, or 100% according to the actual compressor capacity control.

Main Menu

System Setting User Setting Content

Date2009/03/03 CHW In Temp

Ambient Temp Exhaust Temp

CHW Out Temp Condensate Temp

Status Message Closed-down

Comp Running Hrs Running Capacity

Hand/Auto Mode Control Mode Start Interval Modbus

Auto Control Local Control Complete Use

13:05:00 +17.9 °C

+16.9 °C +17.3 °C

+17.9 °C +17.2 °C

2Hr 0%

Fig. 2

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General

Operation & Maintenance Manual 13

User Setting

The user setting is composed of 8 screen cuts. Moving among them is accomplished by the manipulation of the arrow keys . Through user setting, operator can configure control parameters of the chiller. The Control parameters of compressor controls, start mode, control mode and scheduling program. To initiate configuration, press the SET key. With confirming highlighted item after pressing the SET key, the operator can change the value of a digit of the selected item by the arrow keys ‚ or can change the selected digit by the arrow keys . After changing the value of all digits of the selected item, pressing ENT makes the highlighted item to be changed to the next one. Pressing ESC during changing makes the changed to be canceled.

The compressor control parameters (Temp Setting) include chilled water leaving temperature reference setpoint (Target Temp), compressor shutdown temperature (Outage Temp), compressor restart temperature(Restart Temp). The chilled water leaving temperature reference setpoint is desirable temperature configured by the operator. The allowable range of the temperature is 5°C ~ 12°C(41°F ~ 53.6°F). The default value of it is 7°C (44.6°F).

Setting Values

Value Setting Keys

SET

ENTER

Moving to Next Item

ESC

Canceling Setting

Moving to Next Digit

User Setting

I/O Display Main Menu Content

Temp Setting Target Temp

Outage Temp Restart Temp

Mode Selection Control Mode

Hand/Auto Mode Modbus

Time Modify Date Setting

Time Setting

Week Modify

Week Setting Week

Revision Code Oil Preheat 0

Mon Start Mon Stop Tues Start Tues Stop

Sun Start Sun Stop

5 °C ~12 °C

SET

Non-use

SET

Changing Value

7.0

°C

5.0

°C

12.0

°C

Remote

Hand

Use

Local Control

Auto Control

2009/03/03

13:20:10

OFF Mon

Min

OFF Delay

08:00:00 18:00:00 06:00:00 17:00:00

10:00:00 14:30:00

Fig. 3

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General

14 Chiller Air-cooled Screw

Compressor shutdown temperature means the temperature where the compressor must be shut downed by low temperature. Here, the default value is 5.0°C(41°F). Compressor restart temperature means the temperature where the compressor must restart after shutdown. Here the default value is 12°C(53.6°F). By difference between the shutdown temperature and the restart temperature, the compressor is protected from frequent starting.

Operation mode and control mode of main menu are able to be changed in user setting. The operation mode can be either hand or auto. When the operation mode is auto, the chiller runs according to programmed schedule. Contrary, when the start mode is hand, the chiller runs according to key manipulation by operator or remote signal.

The control mode can be either local or remote. When the mode is local, the chiller runs according to key manipulation by operator, Contrary, when the mode is changed to remote, a remote contact is substitute the key operation, and consequently, the chiller can be operated remotely.

Through the time amending, the operator can change system clock. Because the clock is maintained even with power loss, there is no need to set the clock again after power on.

Through the revision code, the operator can change password. Some functions of the HMI unit are protected by the password.

Oil preheating time is also configurable in user setting in the unit of minute.

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General

Operation & Maintenance Manual 15

The I/O display is composed of 9 screen cuts. Through the I/O Display, switch status of signal inputs to the PLC can be identified. In the I/O display, ON means close status of a contact and OFF means open status of contact.

The remote control means remote start input to the PLC. When the contact is closed and the control mode is remote, the chiller starts from stop. When the control mode is local, the switch input is disregarded.

The oil system means the serially connected input of oil flow switch and oil level switch. When both of the oil flow and the oil level are normal during running compressor, both are closed, and consequently the oil system is also closed. When anyone of them is abnormally opened, the switch input to the PLC is also changed into open. The PLC considers the open status of the switch to be oil system alarm.

The compressor contactor switches indicate the status of compressor run. When only the main contactor is closed, the compressor is in the Star-start phase, and when the both of them are closed, the compressor is in the Delta-start phase. Because the contactor switches are contactor status input to the PLC, the contactor inputs must be differentiated from output to the contactors. When there is any problem with a contactor, the input from the contactor and the output the contactor can be different. Consequently, the PLC evaluates the normality of the contactors by checking inputs after making outputs to the contactors be on.

The antifreeze S/W indicated the contact status from the anti-freezing switch. The switch is normally closed, and opens when temperature is under setting value. The PLC considers the openness of the switch to be anti-freezing switch alarm.

The pressure means the serially connected input of high pressure cutout switch and low pressure cutout switch. Both switches are packaged in a dual pressure switch. Both switches are normally open. But if compressor discharge pressure is over the setting value of the high pressure cutout switch or if compressor suction pressure is under the setting value of the low pressure cutout switch, the cutout switch opens. The PLC considers the openness of the switch to be pressure alarm.

I/O Display

User Setting Alarm Display Content

Remote Control System Oil Main Contactor

Contactor

Low Temp Switch Pressure Switch Phase Protect Chilled Flow

Dif-pressure Comp Overload Fan 1A1B Fan 2A3A

Fan4A5A OFF

OFF OFF OFF

Fan2B3B Fan4B5B Emergency Stop

Alarm Output OFF M1 Contactor OFF M2 Contactor OFF M3 Contactor OFF

25% Magnet Valve 50% Magnet Valve

OFF OFF OFF OFF

75% Magnet Valve Pump

Fan1A1B Fan2A3A

Fan4A5A Fan2B3B

Fan4B5B OFF SV2 Magnet Valve OFF

DISCRETE INPUTS2

DISCRETE INPUTS1

DISCRETE INPUTS3

DISCRETE INPUTS4

DISCRETE INPUTS6

DISCRETE INPUTS5

DISCRETE OUTPUT1

DISCRETE OUTPUT2

DISCRETE OUTPUT

OFF OFF OFF OFF

Fig. 4

Page 16

General

16 Chiller Air-cooled Screw

The liquid flow switch detects chilled water flow, and the water flow must build during running the chiller. The openness of the switch during starting up or running compressor is considered to be water flow alarm by the PLC.

The DP switch means differential pressure switch input to the PLC. Normally, the switch must be closed when the compressor runs. The switch opens when the differential pressure between condenser and evaporator is lower than the setting value even with running compressor. The PLC considers the openness of the switch with running compressor to be differential pressure alarm.

The overload switch is compressor internal protector that measures the temperature of motor winding and compressor discharge. When any of the temperatures exceeds predetermined value, the switch opens. The PLC considers the openness of the switch to be compressor overload alarm.

The fan contactor inputs are interconnected with their own overload relay contact, so they must be closed with running fans.

The emergency stop switch must be closed, when the emergency switch is in normal position. When the switch is pushed by operator, the emergency stop switch opens and all output from the PLC are disconnected. The PLC considers the openness of the switch to be emergency alarm.

The discrete outputs generated from the PLC are also displayed on the screen cut. Alarm means the alarm notification to external devices by the PLC. If any system alarm is detected by the PLC, the

alarm will be closed by the PLC. Main contactor, M2 contactor, and M3 contactor are outputs to the magnetic contactors for the compressor. When the

compressor starts, main contactor(M1) and M3 contactor are energized to start the compressor with star winding topology. After a few seconds, the winding topology is changed into delta topology by de-energizing the M3 and energizing M2 instead. During running the compressor, the main contactor and the M2 contactor hold to be energized.

The 25% mgv, 50% mgv, and 75% mgv represent outputs to magnet valves for compressor loading. The magnet valves are installed on the compressor. The capacity control by the control of the magnet valves is shown in the below table.

The fan outputs are outputs to the magnetic contactors of the fans by the PLC.

Step

100% Off Off Off

75% On Off Off 50% Off On Off

MINIMUM Off Off On

Magnet Valve

75% 50% 25%

Table 1

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General

Operation & Maintenance Manual 17

Alarm Display

Through the alarm display, recent 10 alarms are displayed with their invocation time. The alarm also can be cleared in this screen cut. After pressing SET key, the value at affirm entry is changed to clear by

pressing the arrow keys . Pressing ENT key after the value is changed into clear makes the clearance of the alarm history be effective.

Fig. 5

Alarm Display

Delay Setting User Setting Content

Alarm History 1/10 5E Alarm 2009/03/03 Date 12:53:50Time Clear ----

Alarm History 2/10 5E Alarm 2009/03/03 Date 12:53:50Time Clear

Alarm History 10/10 5E Alarm 2009/03/03 Date 12:53:50Time Clear

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General

18 Chiller Air-cooled Screw

System Setting

The system setting is composed of 2 screen cuts. Through the system setting, the temperature readings can be adjusted when there are some problems with the sensor themselves. Additionally running hours can be cleared in this screen. After pressing SET key, the value at running hrs clear entry is changed to clear by pressing the arrow keys

Pressing ENT key after the value is changed into clear makes the clearance of the alarm history be effective.

Fig. 6

System Setting

Main Display Par. Setting Content

Temp and Hours Correction Chilled In

Chilled Out Condensate Temp

Ambient Temp Exhaust Temp Limit Comp Hrs

Clear Comp Hrs

+0.0 °C +0.0 °C +0.0 °C

+0.0 °C +0.0 °C 100000

----

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General

Operation & Maintenance Manual 19

Parameter Setting

Fig. 7

Par. Setting

System Setting Delay Setting Content

Fan Start Temp3 Fan Start Temp2 Fan Start Temp1 Load Interval

Limit Temp Low Temp Outage DT Restart DT

H Exhaust Temp

90.0 °C

SET

10.0~20.0

1.0~5.0

1.0~3.0

SET

1.0~3.0

34.0~37.9

29.0~33.9

25.0~28.9

29.0~200.0

35.0 °C

30.0 °C

26.0 °C 60S

15.0 °C

2.0 °C

80.0~150.0

The system setting is composed of 3 screen cuts. Through the parameter setting, the control parameters of control operations can be identified and changed. To initiate the change, press the SET key. With confirming highlighted item after pressing the SET key, the operator can change the value of a digit of the selected item by the arrow keys or can change the selected digit by the arrow keys . After changing the value of all digits of the selected item, pressing ENT makes the highlighted item to be changed to the next one. Pressing ESC during changing makes the changed to be canceled.

Firstly, Fan control transition points (fan full opening, fan off1, and Fan off2) can be configured. From the transition points, fan full opening means the condenser refrigerant leaving temperature setpoint for running all condenser fans. When actual temperature is over the setpoint, all condenser fans must run. Similarly, the fan off1 means the condenser refrigerant leaving temperature setpoint for running 8 condenser fans. And the fan off2 means the condenser refrigerant leaving temperature setpoint for running 6 condenser fans. Consequently, minimum 6 condenser fans run when the chiller operates, and the number of condenser fans is proportional to the condenser refrigerant leaving temperature. The configurable range is shown in the below picture.

Secondly, system clock can be also changed here. The compressor discharge alarm point temperature cannot be changed only, only informative to operator. The load limit temp is the temperature setpoint where the capacity override is activated. When the chilled water leaving

temperature is over the value, the compressor is prevented from running with 100% capacity and the capacity of the compressor is limited to 75%.

The anti-freezing temp is another method to protect the chiller from too low chilled water temperature additional to antifreezing switch shown in I/O display.

Page 20

General

20 Chiller Air-cooled Screw

Delay Setting

Fig. 8

Delay Setting

Par. Setting Alarm Display Content

Temp Alarm System Oil Water Flow System Pressure

Start Interval Comp Start Delay Comp Stop Delay

Fan Feedback Contactor-feed DP Delay Comp Protect

Fan Stop Delay 30S

SET

15.0~60.0

0.3~1.5

0.3~5.0

90.0~350.0

0.5~1.5

1.0~30.0

10.0~900.0

1.0~20.0

0.0~900.0

8~15 20~200 60~200

3.0S

30.0S

9.0S

3.0S

10Min 30S 60S

2.0S

3.0S

300.0S

1.0S

The delay setting is composed of 3 screen cuts. In this display, control sequence delay and alarm determination delay are configurable.

Start interval is delayed interval between consecutive starts. The delay is counted after the compressor is shut downed and the next start is delayed for the elapse of the time. The startup delay is the delay between water pump run and compressor run at startup phase. When the PLC receives start signal from operator, the PLC initiate the water pump firstly. And after the defined delay, the PLC starts the compressor sequentially.

The outage delay is delay between minimization of the compressor capacity and compressor stop. When the PLC receive stop signal from operator the PLC reset the capacity valves into minimum capacity position. And after the defined delay, the PLC stop the compressor sequentially.

Oil preheat is startup delay of the chiller after receiving start signal. When the chiller is stopped preheating is performed automatically. So through this delay, the preheating time is reserved.

The fan feedback delay is delay to check switch inputs from the magnetic contactors of the fans after energizing the magnetic contactors. Similarly, the contactor feedback is delay to check switch inputs from the magnetic contactors of the compressors after energizing the magnetic contactors.

DP means the delay for the determination of differential pressure alarm after the switch is opened. Comp protect is the delay for the determination of compressor overload alarm by the internal protector of the compressor. Similarly, discharge temp means the delay for the determination of high compressor discharge temperature alarm.

Page 21

Controls

Operation & Maintenance Manual 21

■ PLC and HMI Unit

PLC and HMI Unit

CONTROLS

The HMI (Human Machine Interface) side of the PLC (Programmable Logic Controller) and HMI assembly is shown on the door side as shown in the below picture. The HMI is composed of wide full dot LCD with 4 line display and back light, 9 functional keys, and 15 indicating LEDs for rich user interface.

Through the LCD interface, the operator can monitor the status of chiller operation and control in detail. And the control configurations also can be performed through the LCD interface. For the monitoring and the configuration 7 menu items are prepared in the LCD display from main menu to parameter setting as shown in the below picture. In the below picture, amendable menu contents for the configuration are depicted with shaded color.

Fig. 9

ESC SET ENTER

START STOP

Arrow keys Indicating LED

Full dot LCD :4 line text display with backlight

Page 22

Controls

22 Chiller Air-cooled Screw

Among the menu items, some items are protected from access with authorization code system. The user setting is protected with user code, and delay setting, system setting, and parameter setting are protected from system code. The dual authorization code system enables only authorized operators to configure operation settings, and also enable only service engineers to configure control parameter settings.

The functions of the LEDs are shown in the below table. Through the LED, the operators can identity the status of chiller control without any manipulation.

Fig. 10

Main Menu User Setting I/O Display Alarm Display

System Setting Para. Setting

Delay Setting

Hand/Auto

Mode

Control Mode

Start Interval

Expiration

Chilled Water

In Temp

Ambient

Temp

Exhaust

Temp

Chilled Water

Out Temp

Condensate

Temp Comp

Running Hour

Running

Capacity

Target Temp

Outage Temp

Restart Temp

Hand/Auto

Mode

System Clock

Control Mode

Oil Preheating

Delay

Schedule

Program

Amendable Item

Remote

Control Input

Oil Check

System Input

Comp Contactor

Contact Inputs

Low Temp

Switch Input

Pressure

Switch Input

Phase

Protect Input

Chilled Water

Flow Input

Differential

Pressure Input

Compressor

Overload Input

Fan Contactor Contact Inputs

Emergency

Switch Input

Alarm Output

Comp Contactor

Outputs

Solenoid Valve

Output

Fan Contactor

Outputs

Pump Output

Alarm Clear

Current Alarms

Protected with

User Code

Protected with

System Code

Protected with

System Code

Protected with

System Code

Chilled Water In

Temp Amending

Chilled Water Out

Temp Amending

Cond Ref Out

Temp Amending

Ambient

Temp Amending Comp Discharge

Temp Amending

Comp Running

Hour Clear

Fan Control

Transition Temp

Fan Load

Interval

Comp Discharge

Temp Hi Limit

Chilled Water Out

Temp Hi Ovrd Outage Temp

Restart Temp

Start Interval

Comp Start

Delay

Comp Stop

Delay

Oil Preheat

Delay

Fan Control

Feedback

Comp Control

Feedback

System Code

Comp Overload

Delay

Differential

Pressure Delay Fan Shutdown

Delay

Discharge Temp

Delay

MODBUS

Usage

System Clock

Status Message

Control Mode

MODBUS

Usage

User Code

Comp Loading Valve Outputs

Page 23

Controls

Operation & Maintenance Manual 23

The back side of the PLC and HMI assembly is shown in the below picture. The PLC is composed of base board and extension board. The base board has power connector (POW: CN1), discrete output connector (DO-1: CN2), discrete input connector (DI-1: CN4), and MODBUS communication connector. The extension board has discrete output connector (DO-2: CN3), discrete input connector (DI-2: CN5), and RTD temperature input connector (RTDI: CN6).

LED

OUTPUT1 Auto/Manual Control

Automatic Control: ON Manual Control: OFF

OUTPUT2 Local/Remote Control

Remote Control: ON Local Control: OFF

OUTPUT3 Remote Start Input

Run: ON Stop: OFF

OUTPUT4 Start Interval Lapse

Delaying: ON Complete: OFF

OUTPUT5 Compressor Recycle

Recycle Stop: ON Running: OFF

OUTPUT6

Condenser Coil Warning: ON

Contamination Normal: OFF

OUTPUT7 MODBUS Application

Applying: ON Non-applying: OFF

OUTPUT8 Preheating Application

Applying: ON Non-applying: OFF

OUTPUT9 Preheating Performing

Performing: ON Complete: OFF

Indication

Indicating Status

POW: CN1 DO - 1: CN2 DI - 1: CN4

DO - 2: CN3 DI -

2: CN5

RTDI: CN6

Fig. 11

Table 2. Indicating LED

Page 24

Controls

24 Chiller Air-cooled Screw

On the top side of the PLC, DIP switches and indicating LEDs are installed. Normally, the D2 LED has to blink with 4 Hz frequency, and D3~D6 has to be off. The other LEDs blink according to communication status of the PLC.

All switches of the 4-position DIP switch have to be positioned at off, and switches of the 8-position DIP switch have to indicate MODBUS slave device address. The 8-position DIP switch represents 8 bit hexa number with two digits in inverted value. For example, the factory setting position shown in the below picture (switch2~8: ON and switch 1: OFF) represent 0x7E and its inverted value is 0x01. The factory setting means MODBUS slave address of the chiller is 0x01:

D2D3D4D5D6D7D8D9

12341234

ONONONONONONON

OFF

5678

Modbus Address: 0x01

MODBUS

Communication

RS-232

Communication

PLC Normal:

OFF

4Hz Blink

Fig. 12

Page 25

Controls

Operation & Maintenance Manual 25

Actual locations of the connectors are shown in the above pictures and detail descriptions of the connectors are shown in the below table. The power of discrete outputs is 220VAC and the power of the discrete inputs is 24VDC.

CN5

CN3

CN1 CN2 CN4

Fig. 13

CN6

MODBUS

Fig. 14

Page 26

Controls

26 Chiller Air-cooled Screw

Connector

DescriptionWire No.

CN1

(POW)

AC1 AC2

O01

24VDC-Positive

CN2

(DO-1)

O02 O03

O04 O05 O06 O07 O08 COM

73 74

76 77

24VDC-Ground

Frame Ground System Alarm

M1 Contactor (Main Contactor) M2 Contactor ( Contactor)

M3 Contactor (Wye Contactor) 25% Magnet Comp Loading Valve

50% Magnet Comp Loading Valve 75% Magnet Comp Loading Valve Water Pump

Common: 220VAC Live

Connector

Description

Wire No.

CN3

(DO-

O09 O10

O11

Fan1A1B

O12 O13 O14 O15 O16 COM

81 82 83

85 88 87

Fan2A3A Fan2B3B

SV2 Magnet Valve

Common: 220VAC Live

Table 3

Table 4

Page 27

Controls

Operation & Maintenance Manual 27

Connector

DescriptionWire No.

CN4

(DI-

I01 31

Remote Control I02 32 System Oil Pressure I03 33 I04 34

I05 35 I06 36

Low Water Temperature Switch

I07 37

System Pressure Switch

I08 38

Phase Protector

I09 39

Chilled Water Flow Switch

I10 40

Differential Pressure Switch

I11 41

Comp Overload (Internal Protector)

I12 42

Fan1A1B

I13 43

Fan2A3A

I14 44

Fan2B3B I15 45

I16 46

24V 26 24VDC-Positive 24G 27 24VDC-Ground

M1 Contactor (Main Contactor)

M2 Contactor ( Contactor)

Emergency Switch

Connector Pin DescriptionWire No.

CN5

(DI-

I01~I16

26 24VDC-Positive

24G 27 24VDC-Ground

24V

Table 5

Table 6

Page 28

Controls

28 Chiller Air-cooled Screw

Connector

MODBUS

Description

RX2/D2+

TX2/D2-

Wire No.

MODBUS on RS-485: D+

MODBUS on RS-485: D

CN6

(RTDI)

RTD1+

RTD1-

RTD2+

RTD2-

RTD3+

RTD3RTD3RTD4+

RTD4-

RTD5+

RTD5-

15 14

Chilled Water In Temperature

Chilled Water Out Temperature

Compressor Exhaust Temperature

Ambient Temperature

Refrigerant Cond Out Temperature

Table 7

The MODBUS communication capability is provided by standard. Using the MODBUS communication, the chiller can be integrated in conventional BMS network. The MODBUS also can be translated to LonWorks or BACnet using 3rd party translator for flexible connectivity to BMS network. The communication configuration of the MODBUS communication is as following:

1) Signal: RS-485

2) Mode: RTU

3) Baud rate: 19,200BPS

4) Parity: even

5) Character: 8 Bit

6) Stop Bit: 2 Bit

Page 29

Controls

Operation & Maintenance Manual 29

The MODBUS address map of registers is shown in the below table.

MODBUS Address Meaning Indicating UnitNO Write

46101

Chilled Water Out Temp

Chilled Water In Temp

Ref Cond Out Temp Ambient Temp

Comp Exhaust Temp

Comp Capacity Rate Running Hours

Running Status

Control Status

46102

46103

4 46104 5 46105 6

46106 7 46108 8 46109

46110

10 46115

11 06111

Actual Value x 10 [°C]

Actual Value x 10 [°C] Actual Value x 10 [°C] Actual Value x 10 [°C] Actual Value x 10 [°C]

% Hour

65: Starting, 66: Delaying, 67: Running 68: Shut-downing, 69: Stop

BIT0: Fault, BIT1: Comp Main MC BIT2: Comp MC, BIT3: Comp Y MC

Actual Value(5°C ~ 12°C) x 10 [°C] 0: Stop, 1: Start

YES YES

Table 8

Page 30

Controls

30 Chiller Air-cooled Screw

■ Machine On/off Control

There are two modes to turn on/off the machine. One is the Hand Mode and the other is the Auto Mode. HAND MODE – Hand Mode is the default set mode from the factory, and the user can turn on/off the

power of the product by pressing the Start/Stop button on the control box for 3 seconds. You can set up this mode by selecting [User Setting] and selecting the [Hand Control] from [Hand/Auto Mode].

AUTO MODE – Auto Mode is the mode to control the power on/off of the machine by scheduling the start and stop time. You can set up this mode by selecting [User Setting] and selecting the [Auto Control] from [Hand/Auto Mode]. When the product is shipped from the factory, the default on/off time is set to [Start – 08:00 / Stop – 17:00]. To change the on/off time, set the mode to [Hand Control], and use the button to search the day. When you find the day you want, press the [SET] key and then [ENTER] to move to the row you want to change. Then use the to change the value and press the

to change the set value. After changing the value, press the [ENTER] button. After changing the set value, switch from the [Hand Control] mode to the [Auto Control] mode to schedule the unit to operate at the set time.

The operating key to change the setting is as follows ; [Set] : Change setting / [Enter] : Move down

: Move left/right / : Convert value

• If the Start time is later than the Stop time when you press the [ENTER] button to save the set value, it will return to the default setting.

[Example]

Let’s assume that you want to change the default setting of [Start – 08:00 / Stop – 17:00] to [Start –18:00 / Stop – 22:00]. If you change the Start time to 18:00 first and press the [ENTER] key, the saved

setting will be recognized as [Start –18:00 / Stop – 17:00], and cause an error to return to the default setting of [Start – 08:00 / Stop – 17:00]. In this case, you need to first change the Stop time to 22:00 and then change the Start time to 18:00, the unit can be scheduled to [Start –18:00 / Stop – 22:00].

Page 31

Start-up

Operation & Maintenance Manual 31

■ Pre Start-Up

Do not attempt to start the chiller until the following checks have been completed.

• Check auxiliary facilities, such as the chilled water circulating pump, air-handling equipment, or other equipments to which the chiller supplies liquid are operational. Consult manufacturer’s instructions. If the unit has field-installed accessories, be sure all are properly installed and wired correctly. Refer to unit wiring diagrams.

• Open compressor suction and discharge shutoff valves.

• Open liquid line, oil line, and economizer service valves.

• Fill the chiller fluid circuit with clean water (with recommended inhibitor added) or other non-corrosive fluid to

be cooled. Bleed all air out of high points of system. An air vent is included with the cooler. If outdoor temperatures are expected to be below 32°F(0°C), sufficient inhibited propylene glycol or other suitable corrosion inhibited antifreeze should be added to the chiller water circuit to prevent possible freeze-up. The chilled water loop must be cleaned before the unit is connected.

• Check and inspect all water piping. Make sure flow direction is correct and that piping is made to the correct connection on evaporator and condenser. Open all water flow valves to the evaporator.

• Turn on the chilled water pump manually, measure the water pressure drop across the evaporator, and check that water flow is correct per the design flow rates.

• Check all electrical connections in control panel to be sure they are tight and provide good electrical contact. Connections are tightened at the factory, but can loosen enough in shipment to cause a malfunction.

• Check the actual line voltage to the unit to make sure it is the same as called for on the compressor nameplate, within + 10%, and that phase voltage unbalance does not exceed 5%. Verify that adequate power supply and capacity is available to handle load. To determine percent voltage imbalance: The maximum voltage deviation is the largest difference between a voltage measurement across 2 legs and the average across all 3 legs.

• Verify power supply phase sequence. Fan motors are 3 phase. Check rotation of fans by using the quick test. Fan rotation is counterclockwise as viewed from top of unit. If fan is not turning counterclockwise, reverse 2 of the power wires at the main terminal block.

• Oil separator heaters must be firmly seated under the oil separator, and must be energized for 24 hours prior to start-up. The oil separator should be warm to touch.

• If wind velocity is expected to be greater than 8 km/h wind baffles and brackets must be field-fabricated.

START-UP

Page 32

Start-up

32 Chiller Air-cooled Screw

Do not manually operate contactors. Serious damage to the machine may result. The following procedure should be followed.

• Be sure that water side load such as air-handling equipment, or other equipment to which the chiller supplies liquid are working. Starting of the water side load equipments can be delayed if the chilled water temperature is too high.

• Be sure that water circulating pump is operating if not on automatic control from the chiller.

• Check and inspect all fuses. All fuses inside of the power panel and control panel should be properly located

and maintained.

• Switch on the unit circuit breaker and switch on the start switch installed on the door of control panel.

• Check and inspect the status of the LEDs of the PLC (Programmable Logic Controller) and the HMI (Haman

Machine Interface) unit. The HMI unit should display welcome screen after switching on.

• Check and inspect the voltage monitoring relay inside of the power panel. The relay should not indicate any fault code.

• Using the HMI unit, configure chilled water leaving temperature setpoint.

• Start the system by setting the unit start menu on HMI Unit.

• After running the unit for a short time, check the oil level in each compressor, rotation of condenser fans and

check for flashing in the refrigerant sight glass.

• Ambient temperature during unit operating must be within 64.4°F ~ 129.2°F(18°C ~ 54°C).

• To obtain proper temperature control, water loop volume must be within allowable range of the volume.

■ Start-Up Procedure

Page 33

Start-up

Operation & Maintenance Manual 33

After the above procedure, allow unit to operate and confirm that everything is functional properly. Check to see that chilled water leaving temperature agrees with the setpoint. Additionally, check all sensors to have valid reading values through the HMI unit. The PLC uses 5 RTD thermistors to sense temperatures and the thermistors include: Ambient, Condenser Refrigerant Leaving, Compressor Discharge, Chilled Water Entering, and Chilled Water Leaving.

Temperature (°F) Resistance(Ω) Resistance(Ω) Resistance(Ω)Temperature(°F)

RTD Temperature Vs Resistance Table

Temperature(°F)

-328

-310

-292

-274

-256

-238

-220

-202

-184

-166

-148

-130

-112

-94

-76

-58

-40

-22

-4 14 32

18.49 50 68 86

104 122 140 158 176 194 212 230 248 266 284 302 320 338 356 374 382 410

103.90 428 446 464 482 500 518 536 554 572 590 608 626 644 662 680 698 716 734 752

183.17

22.80 107.79 186.32

27.08 111.67 190.45

31.32 115.54 194.07

35.53 119.40 197.69

39.71 123.24 201.29

43.87 127.07 204.88

48.00 130.89 208.45

52.11 134.70 212.02

56.19 138.50 215.57

60.25 142.29 219.12

64.30 146.06 222.65

68.33 149.82 226.17

72.33 153.58 229.67

76.33 157.31 233.17

80.31 161.04 236.65

84.27 164.76 240.13

88.22 168.46 243.59

92.16 172.16

247.04

96.09 175.84

100.00

179.51

Table 9

Page 34

Start-up

34 Chiller Air-cooled Screw

Temperature

Voltage

Temperature Temperature limits during the operation of the unit are as follows. Maximum ambient temperature: 129.2°F(54°C) Minimum ambient temperature: 64.4°F(18°C) Maximum outlet water temperature: 59°F(15°C) Minimum outlet water temperature: 41°F(5°C) * Temperature of inlet water must not exceed 68°F(20°C) during continuous operation.

Permitted maximum voltage and minimum voltage are displayed on PDB. And if you need other electric data, please refer to PDB. When using the 3 phase voltage, never operate the motor of the compressor when the imbalance among the phases exceed 5% The formula to calculate the voltage imbalance is as follows. % Voltage Imbalance = 100 x (Max Voltage from average voltage / Average Voltage) Max Voltage from average voltage is the absolute value of the maximum gap from the average voltage of the 2 phases.

Example)

Voltage source 400-3phase(1,2,3)-50Hz 12 : 405V / 23 : 394V / 31 : 410V Average voltage : (405 + 394 + 410) / 3 = 403 Difference between average voltage and each voltage : Average – 12 = |403 – 405| = 2V Average – 23 = |403 – 394| = 9V Average – 31 = |403 – 410| = 7V Maximum voltage compared to average voltage : 9V % Voltage imbalance : 100 x (9 / 403) = 2.23% Because the permitted range of the imbalance the voltage is less than 5%, the device can operate.

■ Operation Limits

Page 35

Start-up

Operation & Maintenance Manual 35

Flow Rate

The basic flow rate of the chiller must follow the values of the table showing the maximum, minimum and designed flow rate. Higher or lower flow rates are permitted to make the lower or higher temperature rise. In order to assure appropriate heat exchange and turbulent flow inside the evaporator, the flow rate must exceed the Minimum flow rate.

gpm l/s gpm l/s gpm l/s

RCAW100*BAA

RCAW090*BAA

116.9 7.4 234 14.7 467.6 29.5

107.7 6.8 215 13.6 430.8 27.2

Maximum

Model

Minimum Norminal

Table 10

Compact

Page 36

Start-up

36 Chiller Air-cooled Screw

n Compact

Fig. 15

Note: For flow out of this range, consult LG.

* : P – 380V, Q - 400V, R - 415V

100

120

140

160

0 5 10 15 20 25 30 35

40 RT

60 RT

50 RT

70 RT

80 RT

90 RT

100 RT

Compact model 40 ~ 100 RT

Pressure drop (kPa)

Water flow rate (l/s)

0 50 100 150 200 250 300 350 400 450 500

40 RT

80 RT

60 RT

50 RT

70 RT

90 RT

100 RT

40 RT

60 RT

50 RT

70 RT 80 RT

90 RT

100 RT

40 RT

80 RT

60 RT

50 RT

70 RT

90 RT

100 RT

Compact model 40 ~ 100 RT

Pressure drop (ft wg)

Water flow rate (gpm)

Chilled water pressure drop (SI Unit)

Chilled water pressure drop (English Unit)

Page 37

OPERATION

■ Sequence of Operation

The sequence of the operation is depicted by the flow chart in the below. When the start is in effect, the condenser fan and water pump run concurrently. Additionally, for the minimum load position of the compressor, the MV1 is turned on. After condenser fan feedback delay, the feedback inputs from the contactors are checked. The PLC shutdown the chiller if there is problem with the contactor feedback. Similarly, 9 seconds after the water pump run, water flow is checked.

When there is no problem with the water flow, startup delay is initiated. For the 30~60 second delay, chilled water leaving temperature is checked whether the water temperature is enough high to run the compressor.

When the PLC decides to turn on the compressor, it starts the compressor in star-start, and transits to delta-start after 4 seconds. During starting the compressor, the compressor contactors are also checked whether there is any problem with the feedback from the contactors, and SV1 oil solenoid valve is opened for proper oil circulation.

After the start, normal controls are initiated. The normal controls include capacity control, mid pressure refrigerant control for motor cooling, condenser fan control, and alarm control.

When the chiller is requested to be stopped, the load condition of the compressor is changed into minimum load position by turning on MV1 and Turning off MV2 and MV3. After 60 second of shutdown delay, the compressor is stopped.

Even with the stop of the compressor, the chilled water pump still runs for 4-10 minutes to protect the compressor from frequent restart and to withdraw latent heat from evaporator of the chiller.

The shutdown delay and water pump run delay can be configured in delay setting screen of the HMI unit.

Operation

Operation & Maintenance Manual 37

Page 38

Operation

38 Chiller Air-cooled Screw

Condenser

Fan=ON

Water Pump

= ON

Alarm

Y Start

: M4

: M1=ON & M3=ON : Oil Heater=OFF : Oil Solenoid Valve(SV1)=ON

: Temp Leaving > Setpoint ?

MV1=

: 25%

Alarm

M3 = OFF

DELTA Start

Stop logic

Yes

0.5 Sec

4 Sec

9 Sec

Yes

SecYes

Flow S/W

: 30 - 60 sec

Yes

: M1=ON & M2=ON

Capacity

Control

Mid-pressure

Refrigerant

Valve Control

Alarm

Control

Condenser

Fan Control

: SV2

Y-DELTA START

STOP

Start

Contactor

Check

Flow

Check

Water Temp. Check

Comp.

Contactor

Check

Stop?

Fig. 16

Page 39

Operation

Operation & Maintenance Manual 39

Fig. 17

MV2=OFF & MV3=OFF

MV1=ON, SV2=OFF

M2 =OFF & M1=OFF

SV1=OFF

Water Pump

=OFF

Fan = OFF

4-10Min

Yes

Stop logic

60 Sec

stop

MV1=OFF

Stop?

Page 40

Operation

40 Chiller Air-cooled Screw

Delay control for the chiller is summarized in the below picture. There are two essential delays, stop to start delay and oil pre-heating delay in the picture. The stop to start delay is the duration between the stoppage of the compressor and the restart of the compressor. The factory setting value of the delay is 10 minutes and configurable through delay setting of the HMI unit. The delay is designed to protect the compressor from frequent starting. The other delay, oil pre-heating delay is activated only after power-on reset. The delay is also configurable through user setting of the HMI unit. The delay is designed to protect the cooling cycle of the chiller from improper oil circulation especially at low ambient condition

During running compressor, the condenser fans are controlled to get proper high pressure side condition of the cooling cycle. The control points of the condenser fans are determined by refrigerant leaving condenser temperature, and they are configurable through parameter setting of the HMI unit.

Power on

Reset

Stop to Start

Delay

Oil Pre-heating

Delay

Condenser fan run

Water pump run

START

Compressor Run

Start Delay

Stop

Delay

Fan

Stop

Delay

Fan

Stop

Delay

START

Stop to

Start

Delay

Condenser Fan Run

Water Pump Run

Compressor Run

Start Delay

Stop

Delay

Fig. 18

Page 41

Operation

Operation & Maintenance Manual 41

Fig. 19

Table 11

CONTROL POINT DEFAULT RANGE

T1 34 30 ~ 34 T2 39 35 ~ 39 T3 44 40 ~ 45 T4 - T5 - -

100RT

Page 42

Operation

42 Chiller Air-cooled Screw

To monitor the inlet water temperature, outlet water temperature, discharge temperature of the compressor, ambient temperature and discharge temperature of the condenser of the cooler during chiller operation, RTD (Resistance Temperature Detect) is used.

■ Inlet water temperature sensor of Cooler

■ Outlet water temperature sensor of Cooler

■ Compressor discharge temperature sensor

■ Ambient temperature sensor

■ Condenser discharge temperature sensor

The resistor value for the measured temperature is as follow.

■ Sensors

RTD (Resistance Temperature Detect)

Temperature (°F) Resistance(Ω) Resistance(Ω) Resistance(Ω)Temperature(°F)

RTD Temperature Vs Resistance Table

Temperature(°F)

18.49 103.90 183.17

22.80 107.79 186.32

27.08 111.67 190.45

31.32 115.54 194.07

35.53 119.40 197.69

39.71 123.24 201.29

43.87 127.07 204.88

48.00 130.89 208.45

52.11 134.70 212.02

56.19 138.50 215.57

60.25 142.29 219.12

64.30 146.06 222.65

68.33 149.82 226.17

72.33 153.58 229.67

76.33 157.31 233.17

80.31 161.04 236.65

84.27 164.76 240.13

88.22 168.46 243.59

92.16 172.16

247.04

96.09 175.84

100.00

179.51

-328

-310

-292

-274

-256

-238

-220

-202

-184

-166

-148

-130

-112

-94

-76

-58

-40

-22

-4 14 32

50 68

86 104 122 140 158 176 194 212 230 248 266 284 302 320 338 356 374 382 410

428 446 464 482 500 518 536 554 572 590 608 626 644 662 680 698 716 734 752

Table 12

Page 43

Service

Operation & Maintenance Manual 43

■ Cycle Components

The structure of the air-cooled cooling cycle is shown in the below.

The unit is equipped with semi-hermetic screw compressor developed especially for applications in air-conditioning. The construction of the compressor is shown in the below.

SERVICE

No. PART No. PART No. PART No. PART

(1) Compressor (7) Flow Control Device (13) Oil Level Switch (19) Relief Valve (2) Condenser (8) Flow Control Device (14) Oil Solenoid Valve (20) Temperature Sensor (3) Reciever (9) Dryer (15) Oil Flow Switch (21) Low Pressure Switch (4) Oil Filter (10) Evapolator (16)

Discharge Temp. Sensor

(22) Water Flow Switch

(5)

Oil Seperator / Economizer

(11) Oil Heater (17)

Oil High Pressure Switch

(23) Ref. Solenoid Valve

(6) Flow Control Device (12) Oil Level Sight Glass (18) Anti-freezing Switch (24) Check Valve

Compressor

Table 13

Fig. 21

Fig. 20

Page 44

Service

44 Chiller Air-cooled Screw

As shown in the below, during rotation of the rotors the meshing shifts from the suction side to the discharge side. The meshing rotors enclose a working space, which is continuously reduced as it moves in the axial direction. This causes a V-shaped lobe space to form between each of the male and female lobes. This lobe space increases to a maximum size (suction and sealing process). As the rotors rotate further, the new meshing on the suction side closes the V-shaped lobe space. The lobe space is then constantly reduced by continuing intermeshing of the lobes (compression process).

The reduction in lobe space takes place on the lower side of the rotors towards the discharge side. The volume is steadily reduced and it is thereby compressed in the sealed condition. As soon as the peaks of the rotor teeth are free to the outlet port, the vapor is discharge to the high-pressure side and flows to the oil separator where the high-pressure gas will be separated from the lubrication oil. The size and geometry of the discharge port determine the so called “internal volume ratio (Vi)” of the compressor. This ratio m ust have a defined relationship to operating pressure ratio to avoid losses in efficiency due to under or over compression.

The screw compressor is equipped with 4-step capacity control system. The capacity control system is consisting of a modulation slide valve, piston rod, cylinder, piston and piston rings. The slide valve and the piston are connected by a piston rod. The principle of operation is using the oil pressure to drive the piston in the cylinder. The positive pressure differential causes the piston to move toward the right side in the cylinder. When the slide valve moves toward the right side, the effective compression volume in the compression chamber increases.

Number Description Number Description

1 Compressor casing 18 Discharge fixed ring 2 Motor casing 19 Disc spring 3 Oil separator 20 Bearing lock nut 4 Motor rotor assembly 21 Male rotor 5 Motor stator assembly 22 Suction bearings 6 Motor rotor washer 23 Suction bearings inner/outer spacer ring 7 Motor rotor spacer ring 24 Oil guiding ring 8 Oil separator baffle 25 Suction filter

9 Oil separator cartridge 26 Oil heater 10 Piston 27 Refrigeration Lubricant 11 Piston spring 28 Suction flange 12 Piston rod 29 Discharge flange 13 Bearing seatÅfs cover plate 30 Cable box 14 Modulation solenoid valve 31 Power bolt 15 Modulation slide valve 32 Thermostat terminals 16 Slide valve key 33 Motor cable cover plate 17 Discharge bearings 34 Discharge check valve

Table 14

Fig. 22

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Operation & Maintenance Manual 45

This means the displacement of refrigerant gas also increases, as a result the refrigeration capacity also increases. However, when any of the step solenoid valve is energized, the high pressure oil in the piston cylinder bypasses to the suction port causing the piston and the slide valve to moved toward the left side, then some of the refrigerant gas by pass from the compression chamber back to the suction end. As a result, the refrigeration capacity decreases because of the reduction of displacement of refrigerant gas flowing in the system. The piston spring is used to push the piston back to its original position, i.e. minimum load position in order to reduce the starting current for the next starting-up. If the compressor started at full load capacity it may result in over current start. The capillary is used to maintain and restrain a suitable amount of oil flow into the cylinder. If the oil filter cartridge, capillary, or modulation solenoid valves are not working well in the capacity control system, this may result in the abnormality and ineffectiveness of the capacity control system.

The main functions of the lubrication oil in the screw compressor are lubrication, internal sealing, cooling and capacity control. The positive oil pressure in the cylinder pushes the piston and the slide valve that is connected by a piston rod to move forward and backward in the compression chamber. The design with positive pressure differential lubrication system in the screw compressor is available to omit an extra oil pump in the compressor like reciprocating compressor. However, in some special applications, it is still necessary to install an extra oil pump to the compressor for safety.

Fig. 23

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46 Chiller Air-cooled Screw

The bearings used in the compressor required a small but steady quantity of oil for lubrication; the oil injection into the compression chamber creates an oil sealing film in the compression housing for increasing the efficiency and absorbing a part of heat of compression. In order to separate the oil from the mixed refrigerant gas, an oil separator is required to ensure the least amount of oil carried into the system. Pay more attention to the oil temperature, which has a very significant factor to the compressor bearings’ life. High oil temperature will reduce the oil viscosity and cause the poor lubrication and heat absorption in the compressor as well. The oil viscosity is recommended to keep over 10mm2/ s at any temperature. The oil temperature just keeps above system condensing temperature to avoid the refrigerant migration into system in the summer. There is high oil viscosity in the low ambient temperature circumstance, it could cause compressor in heavy duty to be started up resulting less oil pressure in oil line to load the compressor. The better solution is to have higher condensing temperature in a short time by warming up the oil.

The compressor is equipped two oil sight glasses as a standard, one is the oil high level sight glass, and the other is the oil low level sight glass. The normal oil level in the compressor oil tank should be maintained above the top of the low oil sight glass and in the middle level of high oil sight glass when compressor is running. Applicable oil types are shown in the below.

UNITS

COLOR, ASTM

SPECIFIC GRAVITY

VISCOSITY

FLASH POINT

POUR POINT

T.A.N

COPPER STRIP 100°C/3hr

MOISTURE

FLOC POINT

DIELETRIC STRENGTH2.5mm

104°F

212°F

°F °F

mg KOH/g

ppm

°F

MOBIL EAL ICI EMKARATECPI SOLEST

68 120 220 370 68 100 RL411 RL375 RL421

- - - - 0.5 0.5 1.5 L2.0 L1.0

0.945 0.94 0.95 0.955 0.971 0.966 0.9723 0.9783 0.9759 64 131 215.9 385.96 62.5 95.8 48 74.1 134

8.9 14.53 20.8 29.23 8.3 10.5 7.3 10.1 15

510.8 489.2 519.8 575.6 489.2 500 523.4 474.8 509

-45.4 -33.7 -13 -5.8 -45.4 -34.6 -40 -31 -34.6

- - - - - <0.05 <0.05 <0.05 -

-- - -- - - --

- - - <100 <100 - - - -

-- - -- - - --

Fig. 24

Table 15

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Operation & Maintenance Manual 47

In order to protect the compressor, the compressor has been installed three PTC temperature sensors inside motor coil and another one at the discharge side of compressor. These sensors are connected to an INT69 control module to monitor the motor coil temperature and discharge temperature as well. If the temperature in one of the areas monitored exceeds the nominal response temperature of the respective PTC thermistor, the sensor resistance increases and the INT69 control module switches the motor contactor off. The cutout temperature of the motor winding temperature is 248°F(120°C) and the cut in temperature is 167°F(75°C). The cutout temperature of the motor winding is 230°F(110°C) and the cut in temperature is 140°F(60°C). Compressor trouble shooting is shown in the above.

SYMPTOMS

COMPRESSOR

DOES NOT RUN

COMPRESSOR CYCLES

OFF

ON LOW SATURATED

SUCTION TEMPERATURE

COMPRESSOR

SHUTS

DOWN ON HIGH

PRESSURE

CONTROL

UNIT OPERATES

LONG OR

CONTINUOUSLY

SYSTEM NOISES

COMPRESSOR

LOSES OIL

HOT LIQUID LINE

FROSTED LIQUID LINE

COMPRESSOR LOAD-

ERS NOT WORKING

PROPERLY

CAUSE REMEDY

Check main disconnect. Check control circuit for ground or short. Replace fuse. Use Navigator to reset current alarms. Check connections from CCP to contactor. Check wiring and rewire. Check line voltage. Determine location of voltage drop and remedy deficiency. Check motor winding for open or short. Replace compressor if necessary. Replace compressor. Check oil pump operation, oil pressure transducer, verify oil solenoid valve operation. Repair leak and recharge. Replace transducer. Add refrigerant. Repair/replace as needed. Remove and clean strainer. Replace switch. Open valve or replace if defective. Check wiring. Repair or replace motor(s) if defective. Clean coil. Check wiring. Repair or replace valve if defective. Clean condenser. Add refrigerant. Replace control. Clean or replace. Replace or repair. Evaluate load requirements. Check loader solenoid valves. Replace if necessary. Support piping as required. Add refrigerant. Check for plugged liquid line strainer. Replace compressor (worn bearings). Check for loose compressor bolts securing compressor to cooler. Find and repair leak. Replace compressor. Repair leak and recharge. Open valve or remove restriction. Replace coil. Replace valve. Rewire correctly.

Power line open Control fuse open High-Pressure Switch (HPS) tripped Loose terminal connection Improperly wired controls Low line voltage

Compressor motor defective Seized compressor

Pre-lubrication not successful Loss of charge

Bad transducer Low refrigerant charge Failed expansion device Partially plugged or plugged strainer High-pressure switch erratic in action Compressor discharge valve partially closed Condenser fan(s) not operating (air cooled units) Condenser coil plugged or dirty (air cooled units) Condenser water valve not operating (water cooled units) Circuit overcharged Low refrigerant charge Control contacts fused Partially plugged or plugged strainer Defective insulation Service load exceeding design capacity Inefficient compressor Piping vibration Expansion valve hissing

Compressor noisy Leak in system

Mechanical damage to rotors Shortage of refrigerant due to leak Shutoff valve partially closed or restricted Burned out coil Defective loader solenoid valve Miswired solenoid

Table 16

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48 Chiller Air-cooled Screw

■ Maintenance and cleaning of condenser coil

Periodically cleaning the surface of the coil is essential in maintaining the normal operation of the unit. By removing any contaminant or hazardous substance on the coil, you can extend the life of the coil and the unit. The following maintenance and cleaning method is recommended as part of the periodical maintenance activity to extend the life of the coil.

• Remove fiber on surface : Use the vacuum cleaner to clean any fiber or dust on the surface. If you cannot use the vacuum cleaner, use a soft non-metallic brush to clean the surface. When using both methods to clean the surface, clean in the same direction as the pin. Because the pin can bend very easily, you can bend the pin or scratch the protective coating on the surface by applying the cleaning utensil across the pin.

• Periodical water cleaning: Periodically cleaning the pin with water helps the maintenance of the coil installed on the coast or industrial site. But due to the fragility of the installed coil, you must rinse the coil with water at low speed in order to prevent any damage to the coil. It is recommended to clean once every one to two months.

Condenser

If you use a water hose to clean the coil, be careful as dust or fiber can get inside the coil. Completely remove any fiber or dust on the surface before cleaning it with clean water.

Never use any type of cleaner such as chemical, bleach, acid or alkali cleaner etc. on the coil. These types of cleaners can accelerate the corrosion of the pin and tube, and make it difficult to rinse with water.

Never clean the coil using high speed water or pressured air. Doing so can bend the coil and increase the pressure drop on the air side of the condenser. This can result in performance deterioration or cause the product to stop operating.

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Operation & Maintenance Manual 49

■ Condenser fan

The fan motor and the fan must be fixated firmly on the top plate of the condenser with the metallic bracket. Shroud protects the parts from the fan rotating in high speed. Assembly of the condenser fan is as shown in the picture. as follows. Apply the grease on the exposed part of the motor to protect it from the rain. You have to apply the grease again on the fan axis and then reinstall the Shroud. Also there is an axis support on the fan axis of the fan motor, which must be inserted accurately at this location for maximum performance of the fan motor. And then the bolt must be firmly tightened.

Shrou

Fan

Motor

Fig. 25

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50 Chiller Air-cooled Screw

Cooler

■ Flow Switch

Flow Switch is installed on the water outlet nozzle for all units as factory setting. The following pictures shows the Flow Switch in generally installed method.

Fig. 26

Table 17

parts name Qty cover insulation plate microswitch adjusting screw metal fitting for flow adjusting screw flow adjusting screw actuating plate adjusting spring

1 1 1 1

1 1

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Operation & Maintenance Manual 51

■ Dual Pressure Switch

■ Differential Pressure Switch

Differential pressure switch is also used for checking lubrication trouble. When the differential pressure between condenser and evaporator is larger than the setting value(5kg/cm2), the switch will be closed. Contrary, when the setting value is under the setting value, the switch will be opened. This switch is also returned to be closed automatically when the differential pressure is recovered from low pressure status.

Dual pressure switch has low pressure cutout switch and high pressure cutout switch inside. The cutoff points can be adjustable. The factory setting values are shown in the below.

The low pressure switch and the high pressure switch are normally closed and tripped to opening when the detected pressure exceeds the setting value. After recovering from high pressure or low pressure status, the switch resets to normal position automatically.

Low Pressure Cutout 3.2kgf/cm

High Pressure Cutout 22kgf/cm

Table 18

Fig. 27

Fig. 28

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52 Chiller Air-cooled Screw

■ Anti-freezing Switch

The anti-freezing switch is used to detect too low water temperature. The switch is normally closed and tripped when the chilled water leaving temperature is under 35.6°F(2°C). The switch returns to the normal status when the temperature increases over 41°F(5°C). The Anti-freezing switch is installed on the evaporator.

Fig. 29

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Operation & Maintenance Manual 53

Refrigerant Cycle

■ Leakage test

As described in the installation manual, the unit is sufficiently charged with R134a refrigerant as factory setting. If the refrigerant pressure is lower than the factory setting, you must check for leakage. If the pressure inside the unit has dropped, use the Nitrogen to do a leakage test. When repairing the leaking part, you must use good refrigeration practice. After the leakage is repaired, any water inside the chiller must be removed and vacuumed.

■ Charging the refrigerant

Insert the coupling to the refrigerant charging port. In order to avoid the damage to the tube from residual water freezing within the evaporator, circulate the water in the evaporator (EVA) while charging the refrigerant to the designated amount. For the amount of refrigerant to charge, refer to the installation manual or PDB.

■ Charging the oil

Insert the coupling in the oil port. Check whether the oil level is above in the Sight Glass window. Remove the coupling and insert the oil port cap. After inserting the oil, operate the product and check whether the oil level is above with the naked eye. If not, supplement the oil.

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54 Chiller Air-cooled Screw

■ Oil Filter

The oil filter is installed on the oil separator in oil return line to the compressor. Differential pressure between the inlet and outlet of the oil filter must be checked periodically. On the oil separator, the core valves for connection of the inlet/outlet with pressure gauge are installed. If the differential pressure is over 5kg/cm2it is recommended to disassemble the oil filter and wash the oil filter mesh.

■ Oil Flow Switch

The oil flow switch is also installed on the oil separator in oil return line to the compressor. The setpoint range of the flow switch covers 3.4~4.2 l/min at increasing flow and 3.0~3.8 l/min at decreasing flow. Maximum flow rate of the oil flow switch is 67l/min.

Item Name Note Qty

Bolt M10 x 40L 8 Service flange Ø136 x 15t 1 Gasket Ø90 x 1.5t 1 Spring Ø37 x 2d 1 Oil Filter Cartridge 30 mesh/inch 1 O-ring Ø28.24 x 2.62W 1 Oil filter Body Ø136 x 270L 1

Refrigerant Cycle

Fig. 30

Fig. 31

Table 19

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Operation & Maintenance Manual 55

■ Oil Heater

■ Solenoid Valve

One of the Solenoid Valve is installed between the Flash Gas Tank where the oil separator is installed and the other is installed between the oil filter and Flash Gas Tank. Valve on the compressor side is turned on during Full Load operation, and off during other operations. Valve on the oil filter side is turned on when the unit is operating to pass the oil to the compressor, and off when the operation stops to prevent the oil from back flowing.

The oil heater prevents poor lubrication due to too low viscosity. The oil heater is also installed on the oil separator. The 150W oil heater has 220VAC power input.

Fig. 32

Fig. 33

Include Cable wire Include DIN plug wire

3.3689585755445252817213838351-3/8

3.0689585755445222567213838281-1/8

EVR25

kgmmmmmmmmmmmmmmmmmmmmmmmmmmin

12/20W10W

weight

Max

max

Connect

MODEL

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56 Chiller Air-cooled Screw

■ Control System

The structures of the power panel and control panel are shown in the below. The power panel in the left is composed of the electrical components related to 400VAC main power, and the control in the right is composed of low-voltage components such as the PLC and the HMI unit.

Both panels are designed to be water proof by dual door system. The panels comply with IP55.

ontrol Panel

ower Panel

Fig. 34

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Operation & Maintenance Manual 57

Power Panel

On the left side of the power panel, terminal blocks for main power connection are prepared. The field supplied 400VAC main power lines and neutral line for control power are connected to these terminal blocks.

There are three magnetic contactors for the wye-delta starting of the compressor and OCR (Over Current Relay) for the compressor. For wye-delta starting, there are three magnetic contactors installed inside of the power panel.

By the wye-delta starter, the starting inrush current is reduced by 1/3 of direct starting method. The line voltage(VL) of the both of wye and delta winding configuration is 400VAC, but the phase voltages(VP) of the wye winding configuration is reduced by 1/3 of the delta winding configuration. Additionally, the line current (IL) is also reduced by 1/3 of the delta winding configuration. Consequently, the current of the wye winding configuration is reduced by 1/3 of delta winding configuration. Using the principle, the compressor starts with the wye winding configuration. And the winding configuration is changed into delta configuration after few seconds for the normal operation of the compressor.

Fig. 35

Main Power

Compressor Wye-delta Starter

Compressor OCR

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58 Chiller Air-cooled Screw

PLII=

Wye Starting Delta Running

L3 L2

LPVV=

IIx

Fan contactor & OCR

Fuse assembly

Voltage monitoring relay : 5E

Fuse for the 5E Power input

Fig. 36

Fig. 37

There is one magnetic contactor for each condenser fan. On the right bottom side of the power panel, voltage monitoring relay is installed to monitor proper power input. There

are three fuses installed for the 400VAC power input to the voltage monitoring relay. The ventilation fan of the power panel is controlled by the thermostat. If the ambient temperature inside of the power panel is over 95°F(35°C), the ventilation fan runs.

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Operation & Maintenance Manual 59

n Compressor OCR (Over Current Relay)

The compressor OCR is thermal type and used to protect the compressor from overload condition. The OCR contact used for the control system is normally closed and the OCR contact switch is to be opened if it detects excessive current. The OCR needs manual reset by switch on the OCR to be recovered to normal after tripping. The tripping point ranges and factory settings are shown in the below table

n Condenser Fan OCR

The condenser fan OCR is also thermal type and used to protect the condenser fan from overload condition. The OCR contact used for the control system is normally closed, and the OCR contact switch is to be opened if it detects excessive current. The OCR needs manual reset by switch on the OCR to be recovered to normal after tripping. The tripping point ranges and factory settings are shown in the below table.

Model Range[A] Trip[A]

RCAW090PBAA 165~235 177

RCAW1008BAA 165~235 173

Model Range[A] Trip[A]

RCAW090PBAA 6.5~8.5 8

RCAW1008BAA 4.5~6.5 6.2

Table 20

Table 21

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60 Chiller Air-cooled Screw

n Voltage Monitoring Relay (5E)

The voltage monitoring relay is used for the verification of proper power supply of 400VAC. The voltage monitoring relay is shown in the below. Existing 3-phase voltage will be shown ordinally every 3 seconds as shown in the below.

The voltage monitoring relay monitors 5 abnormal conditions of the power supply. The abnormal conditions include over voltage, under voltage, phase reverse, phase loss, and voltage unbalance. Among the abnormal conditions, the phase reverse and the voltage unbalance are selectively protective. The others are mandatory. When any abnormal condition is encountered, the type of abnormal condition and abnormal value detected are displayed instead of normal display. Some examples of the abnormal conditions are shown in the below.

Along with the selectivity of protection, reset method after any abnormal condition invocation can be configured through 4-position DIP switches. The functions of the DIP switches are shown in the below. According to factory setting, only the switch positioned at ʻ5S/1Sʼ is off, and the others are on. Please don't change factory setting for proper protection.

R S T

UNDER VOLTAGE

UNBALANCE VOLTAGE

PHASE LOSS NO INPUT

OVER VOLTAGE REVERSE PHASE

R S T

Fig. 38

Fig. 39

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Operation & Maintenance Manual 61

The voltage unbalance tripping is activated when the unbalance exceeds +5% more than 3 seconds. Similarly, phase loss tripping has 2 second delay and phase reverse tripping has 0.5 second delay.

The over voltage tripping point and tripping delay are configurable through rotary switch on the voltage monitoring relay. The under voltage tripping point and tripping delay are also configurable through another rotary switch on the voltage monitoring relay. The factory setting of the rotary switches are shown in the below table.

Rate Voltage 380VAC 400VAC

Over Voltage Value 416VAC 440VAC

Over Voltage Delay 4S

Under Voltage Value 342VAC 360VAC

Under Voltage Delay 4S

Table 23

Table 22

REV.

UNBAL.

AUTO

5S/1S

OFF

Reverse phase protected

Reverse phase unprotected

Unbalance protected

Unbalance unprotected

Auto reset

Manual reset

Auto reset delay 5 sec

Auto reset delay 1 sec

OFF

UNBAL.

AUTO

5S 1S

REV.

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62 Chiller Air-cooled Screw

■ Assist Relay

Assist Relay is the relay to check power supply of 220V to the controller. Assist Relay is as follows.

■ Compressor Contactor

Compressor Contactor controls the start, stop and static range of the compressor motor when the product is operating. Rated voltage of Compressor Contactor is 400V.

Fig. 40

Fig. 41

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Operation & Maintenance Manual 63

■ Fan Contactor

Fan Contactor controls the start, stop and static range of the fan motor when the product is operating. Rated voltage of Fan Contactor is 400V.

Fig. 42

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64 Chiller Air-cooled Screw

Control Panel

On the external door of the control panel there is emergency switch for the instant cutting out of control outputs from the PLC. By pushing the emergency switch, the 220VAC power supplied to the PLC relay outputs are cut out instantly. By turning the switch in clock-wise direction, the power to the output is recovered.

On the internal door of the control panel, operator can access the HMI unit. Along with the HMI unit, power indication lamp and start/stop switch are installed on the door. The start/stop switch is to switch on or off the control power to the control system, and the power supply status is indicated through the power lamp.

Sight glass for the HMI unit & PLC

Emergency switch

HMI unit & PLC

Power lamp

External Door of Control Panel

Internal Door of Control Panel

Fig. 43

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Operation & Maintenance Manual 65

In the control panel, the PLC is installed as a central control station. The PLC is assembled with the HMI unit in a black case. The PLC is supplied 24VDC power from the SMPS (Switched Mode Power Supply) on the right side.

The relay is to confirm proper 220VAC power supply and start/stop switch which is installed on the door is positioned at start. The ventilation fan of the control panel runs permanently after power on.

Control fuse

Control Relay

Switched Mode Power Supply

Fig. 44

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66 Chiller Air-cooled Screw

ETC

■ Temp. Sensor in Control Box

This is used to detecting the temperature within the Control Box when operating the product. The shapes and characteristics are as follows.

■ Ventilation Fan

Ventilation Fan is attached on both sides of the Power Box and the Control Box. This fan responds to the temperature increase within both boxes while the product is operating and sends the air outside to prevent any issues from temperature increase within each box.

Fig. 45

Fig. 46

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Operation & Maintenance Manual 67

■ Maintenance

Maintenance Schedule

Check Point

Daily Monthly

Every

2 months

Every

3 months

Every

6 months

Every

1 year

Every

2 years

Every

3 years

Every

6 years

1. Cycle Status

Check

2. Electric part

Check

Monthly check

3. Safety switches

Check Monthly check

4. Water Loop System

Check

Clean

Check every 6 months

5. Condenser cleanness

Check

6. Cooling tower cleanness

Check Clean Annual clean

7. Refrigerant system leakage

Check

Monthly check

8. Oil filter

Check

Replace

Check every 6 months. Clean if necessary.

9. Dryer filter

Check

Replace

Annual replacement

10. Oil Level

Check

Annual check

11. Oil color

Check

Replace

12. Compressor insulation

Check

Annual check

13. Temperature sensor

Check

Check every 6 months

14. Compressor bearing

Check

Check or

replace

Check every 6 months. When the operating pressure

of the cooler is out of the range, clean the unit.

10h 500h 1000h 1500h 2500h 5000h 10000h 15000h 30000h

---

-- -

Table 24

Page 68

Trouble Shooting

68 Chiller Air-cooled Screw

If a stoppage occurs more than once as a result of any of the safety devices, determine and correct the cause before attempting another restart.

TROUBLE SHOOTING

General Malfunction

Before specific alarm trouble shooting, general troubles and their possible remedies are introduced. When the unit does not run at all, you have to check power supply to the chiller, refrigerant, configuration, and alarm invocation. For the power supply check, you have to check voltage applied to the terminal block inside of the power panel. If the power is absent, please check power feeder and check whether any protective device is tripped.

When the power is applied properly, refrigerant pressure must be inspected by pressure gauge installed on the chiller, when the pressure is out of range, please check whether any leakage point is by soap bubble test. If there is problem with the configuration of the PLC or too much delay is configured, the chiller will not start or the start is delayed for long time. Please recover the configuration value to factory setting before starting the chiller. Lastly, alarm invocation has to be checked. You can find whether any alarm is invoked through the HMI unit. Follow specific alarm trouble shooting procedure if any alarm is invoked. Normally, the compressor of the chiller will cycle according to the chilled water leaving temperature, the compressor shutdown temperature and the compressor restart temperature. But the case where the compressor runs too long without cycling can be encountered. When the refrigerant is not enough, the chiller will operate continuously because the chiller cannot work at 100% power. At this case, the leakage is also to be inspected. When magnetic contactors for the compressor are mechanically welded, the chiller operation will be continued, because the PLC cannot stop the compressor by control signal even if the compressor must be stopped. When there is no problem with the refrigerant and compressor contactor, Air inside of the water loop can be a cause, because air inside of water loop obstructs thermal exchange. When the problem is revealed, the air must be purged. When there is non-condensables in the refrigerant circuit, remove the refrigerant and recharge. Even after running condenser fan and chilled water pump, the compressor will not run caused by alarm or trouble with temperature reading. Please follow specific alarm trouble shooting procedure at this case.

Page 69

Trouble Shooting

Operation & Maintenance Manual 69

Symptom

Unit does not run

Compressor operates too long continuously

Possible Cause

Possible Remedy

Check over current protection device Check no-fused disconnect (if equipped) Restore power to unit

Check for leak and add refrigerant Check unit configuration

Check Alarm status. See separate alarm trouble shooting procedure and follow trouble shooting instructions Check the PLC input channels also to verify alarm status Input

Check fulfillment of oil heating time Check fulfillment of comp start delay time Check chilled water temp out Check water flow

Check for leak and add refrigerant Replace the contactors

Purge water loop Remove refrigerant and recharge

Check Alarm status. See separate alarm trouble shooting procedure and follow trouble shooting instructions

Check for temperature inputs. See operation and control. Check capacity control overrides Check the PLC input channels also to verify alarm status Input

Check for power to unit

Low refrigerant charge Wrong or incorrect unit

configuration Active alarm

Active operating mode

Low refrigerant charge Compressor or control con-

tacts welded Air in chilled water loop Non-condensables in refriger-

ant circuit Active alarm

Active operating mode

Table 25

Circuit does not run

Page 70

Trouble Shooting

70 Chiller Air-cooled Screw

Alarm

Specific alarms, their recognition method, and their possible causes are listed here. To clear alarm and recover from the alarm, clear the alarm history after correction of the cause of the alarm.

The emergency trouble means that the emergency switch installed on the right side of the control panel is pushed by operator. This switch input is normally closed and the trouble means the switch input is opened. When the emergency switch is opened output power for the output control from the PLC is disconnected. By pulling the emergency switch, the alarm can be corrected.

5E relay, voltage monitoring relay signals alarm when there is trouble with the power supply. The trouble includes over voltage, under voltage, reversed phase, phase loss, and voltage unbalance. Please be sure that all fuses for detecting of power supply are not melted in case of phase loss alarm.

Liquid flow trouble means the absence of water flow or shortage of the water flow under 70% of rated water at default value. Water pump malfunction and shortage of water volume must be observed concurrently to solve the problem.

Pressure trouble means tripping of high pressure cutout switch or low pressure cutout switch. Both of them are packaged in dual pressure switch. When the problem is encountered, proper amount of the refrigerant inside of the chiller must be inspected firstly. If there is no problem with the amount of the refrigerant, contaminated heat exchanger can be a reason. Please consider the operating ambient temperature range of the chiller is from 64.4°F~129.2°F(18°C~54°C).

Oil trouble means oil flow absence from the oil separator to the compressor or low oil level in the oil separator. This alarm is checked after 120 second after running the compressor.

The delay is adjustable through delay setting of the HMI unit. Shortage of oil must be inspected firstly. When the chiller runs under low ambient temperature without enough pre-heating, much amount of oil can be remained in evaporator instead of the oil separator. In this case, oil must be added up to the oil separator.

Low differential pressure between the evaporator and the condenser will not guarantee proper oil circulation, so the differential pressure must be inspected through pressure gauge.

M1 and M2 are magnetic contactors for screw compressor. The malfunctions of the magnetic contactors mean OCR trip by overload condition or problem with the contacts of the magnetic contactors themselves.

INT69 trouble means that the internal protector inside of terminal box of the compressor detect abnormally high temperature on the motor winding or compressor discharge.

There can be two sources for the anti-freezing S/W trouble. Actually, the alarm is recognized by tripping of anti-freezing switch of low water temperature detected by temperature sensor. In case of the low water temperature, the setting point for the determination of the alarm can be changed by HMI unit.

When there is mechanically welded contact problem with the magnetic contactors for the compressor, the PLC cannot stop the compressor and consequently you can encounter this alarm at the case. Therefore, in this case you must turn off the circuit breaker located before the malfunctioning magnetic contactor.

Fan trouble is similar with the M1 or M2 trouble in the case of the compressor. It means OCR trip by overload condition or problem with the contacts of the magnetic contactors.

Discharge temp trouble is invoked when the compressor discharge temperature is over 176°F(80°C). This can be caused by shortage of refrigerant or too high ambient temperature

COMM fault trouble means communication failure between the HMI unit and the PLC, loosed connection is frequently encountered cause the trouble

Page 71

Trouble Shooting

Operation & Maintenance Manual 71

Displayed Alarm

Message

Recognition

Possible Cause

Possible Remedy

• Turn the emergency switch clockwise to return

• Emergency switch input(switch off)

• Trip of emergency

Emergency Stop

• Review chilled CHW temperature, ambient temperature or applicable sensor

• Trip of differential pressure switch (switch off) after the compressor run (default: DP < 4kgf/cm2)

• Too high chilled CHW temperature

• Too low ambient temperature

Dp Alarm

• Check power

• Repair or replace 5E protective

switch

• Trip of voltage monitoring relay (switch off)

• Over voltage

• Under voltage

• Reversed phase

• Voltage unbalance

• Missing phase

5E Alarm

• Repair or replace CHW pump

• Remove air and supplement

water

• CHW line side valve open

• Flow switch setting or device

error

• CHW flow switch input (switch off) after the CHW pump run

• CHW pump malfunction

• Shortage of CHW volume

• CHW line side valve closed

• Flow switch setting or device

error

Waterflow Alarm

• Remove over charging refrigerant

• Repair or replace high pressure switch

• Vacuum and recharge after removing refrigerant

• Adjust high pressure switch setting

• Repair or replace controller

• Charge additional refrigerant

• Repair or replace an external fan

motor

• Trip of high pressure switch

• Over charge of refrigerant

• High pressure switch error

• Air mixed into refrigerant

• High pressure switch setting too

low

• Controller DI point error

• Insufficient refrigerant

• External fan motor error

Pressure Alarm

Page 72

Displayed Alarm

Message

Recognition

Possible Cause

Possible Remedy

Trouble Shooting

72 Chiller Air-cooled Screw

• Charge additional refrigerant

• Test/Repair as necessary and

charge additional refrigerant

• Adjust low pressure switch setting

• Repair or replace Low pressure

switch

• Repair or replace controller

• Trip of low pressure

switch

• Insufficient refrigerant

• Refrigerant leakage

• Low pressure switch setting too

high

• Low pressure switch error

• Controller DI point error

Pressure Alarm

• Replace oil dryer

• Replace oil service valve

• Repair or replace oil flow switch

• Repair or replace controller

• Supplement oil

• Oil flow switch input

(switch off) 120 second after the compressor run

• Oil dryer clogged

• Oil service valve error or closed

• Oil flow switch error

• Controller DI error

• Shortage of oil

• Replace oil level switch

• Repair or replace controller

• Supplement oil

• Oil level switch input

(switch off) 120 second after the compressor run

• Oil level switch error

• Controller DI point error

• Shortage of oil

System Oil Alarm

• Replace M1 contactor

• Check voltage, check condenser

fan motor, clean heat exchanger, repair overload relay, repair or replace compressor

• Repair or replace controller

• M1 magnetic contactor

contact input or overload relay contact input (switch off) after the compressor run

• Malfunction of M1

• Compressor overload

• Controller DI or DO point error

M1 Contactor Alarm

• Replace M2 contactor

• Repair or replace controller

• M2 magnetic contactor

contact input after the compressor run

• Malfunction of M2

• Controller DI or DO point error

M2 Contactor Alarm

Page 73

Displayed Alarm

Message

Recognition

Possible Cause

Possible Remedy

Trouble Shooting

Operation & Maintenance Manual 73

• Review voltage

• Repair or replace controller

• Test or replace comp

• Test or replace internal protective

switch

• Check condenser fan motor

• Clean condenser fin

• Trip of compressor

internal protector (switch off) by high compressor winding temperature

• Voltage error

• Controller DI or DO point error

• Comp error

• Internal protective switch error

• Condenser fan motor error

• Contamination of condenser fin.

Comp overload Alarm

• Charge additional refrigerant or review valve condition

• Repair or replace controller

• Repair comp

• Test or replace internal protec-

tive switch

• Check ambient temperature

• Trip of compressor

internal protector (switch off) by high discharge temperature

• Refrigerant flow rate insufficient

• Controller AI point error

• Comp error

• Internal protective switch error

• Too high ambient temperature.

• Increase CHW flow or replace

pump

• Increase set value of chilled CHW temp out

• Lower anti-freezing set value

• Replace anti-freezing switch

• Check ambient temperature

• Repair or replace controller

• Supplement refrigerant

• Clean cooler

• Replace M1 or M2

•

Trip of anti-freezing switch (switch off) (Default: chiller CHW temp out ≤ 35.6°F(2°C)

• CHW flow insufficient

• Too low set value of chilled CHW

temp out

• Too high anti-freezing set value

• Anti-freezing switch error

• Too low ambient temperature

• Controller DI error

• Refrigerant insufficient

• Contamination of cooler

• Malfunction of M1 or M2

Low temp

Page 74

Displayed Alarm

Message

Recognition

Possible Cause

Possible Remedy

Trouble Shooting

74 Chiller Air-cooled Screw

• Charge additional refrigerant or review valve condition

• Repair comp

• Check ambient temperature

• Compressor discharge

temperature is over ≤194°F(90°C) after the compressor run

• Refrigerant flow rate insufficient

• Comp error

• Too high ambient temperature

Exhaust Temp Alarm

• Check connection between PLC and HMI unit

• Communication failure

• Communication failure between

the PLC and the HMI unit

Contact fault alarm

• Replace FAN1A1B motor, check magnetic contactor or relay

• Check FAN1A1B lock

• FAN1A1B magnetic

contactor contact input or overload relay contact input (switch off) after the compressor run

• Malfunction of FAN1A1B

• Condenser FAN1A1B overload

FAN1A1B Alarm

• Replace FAN2A3A motor, check magnetic contactor or relay

• Check FAN2A3A lock

• FAN2A3A magnetic

contactor contact input or overload relay contact input (switch off) after the compressor run

• Malfunction of FAN2A3A

• Condenser FAN2A3A overload

FAN2A3A Alarm

• Replace FAN4A5A motor, check magnetic contactor or relay

• Check FAN4A5A lock

• FAN4A5A magnetic

contactor contact input or overload relay contact input (switch off) after the compressor run

• Malfunction of FAN4A5A

• Condenser FAN4A5A overload

FAN4A5A Alarm

Page 75

Displayed Alarm

Message

Recognition

Possible Cause

Possible Remedy

Trouble Shooting

Operation & Maintenance Manual 75

FAN2B3B Alarm

FAN4B5B Alarm

Exhaust temp sensor close

Exhaust temp sensor open

CHW In temp sensor close

CHW In temp sensor open

CHW out temp sensor close

CHW out temp sensor open

Condensate temp close

Condensate temp open

Ambient temp close

Ambient temp open

• FAN2B3B magnetic contactor contact input or overload relay contact input (switch off) after the compressor run

• FAN4B5B magnetic contactor contact input or overload relay contact input (switch off) after the compressor run

• Compressor discharge temperature sensor close

• Compressor discharge temperature sensor open

• Chilled water in temperature sensor close

• Chilled water in temperature sensor open

• Chilled water out temperature sensor close

• Chilled water out temperature sensor open

• Condensation temperature sensor close

• Condensation temperature sensor open

• Ambient temperature sensor close

• Ambient temperature sensor open

• Malfunction of FAN2B3B

• Condenser FAN2B3B overload

• Malfunction of FAN4B5B

• Condenser FAN4B5B overload

• Sensor line is short

• Malfunction of Sensor

• Sensor line is cut out or loose

• Malfunction of Sensor

• Sensor line is short

• Malfunction of Sensor

• Sensor line is cut out or loose

• Malfunction of Sensor

• Sensor line is short

• Malfunction of Sensor

• Sensor line is cut out or loose

• Malfunction of Sensor

• Sensor line is short

• Malfunction of Sensor

• Sensor line is cut out or loose

• Malfunction of Sensor

• Sensor line is short

• Malfunction of Sensor

• Sensor line is cut out or loose

• Malfunction of Sensor

• Replace FAN2B3B motor, check

magnetic contactor or relay

• Check FAN2B3B lock

• Replace FAN4B5B motor, check

magnetic contactor or relay

• Check FAN4B5B lock

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

• Check sensor line

• Change sensor

Table 26

Page 76

Appendix

76 Chiller Air-cooled Screw

Appendix

■ Wiring Diagram

Fig. 47

SYMBOL

Fuses

P/Box Heat dissipation fan

LEGEND

DESCRIPTION

Assist relay

C/Box Heat dissipation fan

Oil heater

Inner temperature controller

Oil seperator sol. v/v

Comp. capacity control v/v

Mid pressure air charging sol. v/v

Comp. magnetic switch 1

F1~F3

CF1

CF2

R1 R2

CCH1

THC

SV1

SV2

M2M1 M3

M1M2M3

Comp. magnetic switch 2 ( )

Comp. magnetic switch 3 ( Y )

Fan1A~Fan4A over current relays

Comp over current relay

Fan1A~Fan4A magnet contactors

FN1A ~ FN4A

FN1B ~ FN4B

Fan1B~Fan4B magnet contactors

OLC1

OLF1A ~ OLF4A

OLF1B ~ OLF4B

Fan1B~Fan4B over current relays

Power indicator lamp

Emergency switch

SW1

Low pressure switch

Reverse phase protector

High pressure switch

Mold option switch

RST

VOLTAGE

MONITORING

(5E)

TO MAN CONTROL

UNIT

220VAC

CF1

CF2

START/STOP SWITCH

220VAC

SMPS

-V+V

26 27

24VDC-P

24VDC-G

COOLER IN TEMP

COOLER OUT TEMP

COMP DISCHARGE TEMP

AMBIENT TEMP

COND OUT TEMP

26 27 1011 1213141516 17 18 19 27 26 31 32 3334 35 36 37 38 39

43 44 45

27 26

REMOTE RUN

OIL FLOW OIL FLOW

OLC1 M1

ANTI-FREEZING

LP HP

CHILLED WATER FLOW

HIGH-LOW DIFFERENTIAL

INT69

OLF1A

OLF2A

OLF2B

FN1A

FN2A

FN2B

101

OLF1B

OLF3B

FN1B

FN3A

FN3B

104

110

102

105

111

103

106

112

EMERGENCY SWITCH

RTD1

+24V

-24V

RTD1 RTD2RTD2 RTD3RTD3 RTD4 RTD4 RTD5 RTD5

-(2) +(1) -(4) +(3) -(6) +(5) -(8) +(7) -(10) +(9)

24V-G IO1 IO2 IO3 IO4 IO5 IO6 IO7 IO8 IO9 I10 I11 I12 I13 I14 I15 I16

COM O01 O02 O03 O04 O05 O06 O07 O08 O09 O10 O11 O12 O13 O14 O15 O16 O17 O18 O19 O20COM

7 71 72 73 74 75 76 77 78 7 79 80 81 85

CHILLED WATER PUMP

SV1

M3 MV1 MV2

MV3

FN1A FN1B FN2A FN2B FN3A FN3B

FAULT

A1 A1 A1

A2 A2 A2

A1 A1 A1 A1

A2 A2 A2 A2 A2 A2

EMRG

HMI

UNI

MAIN CONTROL UNIT

Output (Primary) Output (Secondary)

Intput (Primary)

Intput (Secondary)

FAN 1B FAN 2B FAN 3B

OLF1B

4.5A (3.5-5)

OLF2B

4.5A (3.5-5)

OLF3B

4.5A (3.5-5)

1L1 3L2 5L3 1L1 3L2 5L3 1L1 3L2 5L3

2T1 4T2 6T3 2T1 4T2 6T3 2T1 4T2 6T3

FN1B FN2B FN3B

FAN 1A FAN 2A FAN 3A

40472

INTERNAL

PROTECTOR

(INT69)

11122

OLF1A

4.5A (3.5-5)

OLF2A

4.5A (3.5-5)

OLF3A

4.5A (3.5-5)

FN1A FN2A FN3

2T1

4T2 6T3

2T1

4T2 6T3

1L1

3L2 5L3

1L1

3L2 5L3

OLC1

107A

(100~135)

202

M1 F2

CCH1

THC

COMP

TO MAIN CONTROL UNIT

400VAC3P 4W

M2 M1

97 98

24V 24V-G 24V

Transformer

301

302

303 304

301

302

304305

CCW COM

COM

SV2

RCAW1008

Page 77

Appendix

Operation & Maintenance Manual 77

Fig. 48

SYMBOL

Fuses

P/Box Heat dissipation fan

LEGEND

DESCRIPTION

Assist relay

C/Box Heat dissipation fan

Oil heater

Inner temperature controller

Oil seperator sol. v/v

Comp. capacity control v/v

Mid pressure air charging sol. v/v

Comp. magnetic switch 1

F1~F3

CF1

CF2

CCH1

THC

SV1

SV2

M2M1 M3

M1M2M3

Comp. magnetic switch 2 ( )

Comp. magnetic switch 3 ( Y )

Fan1A~Fan4A over current relays

Comp over current relay

Fan1A~Fan4A magnet contactors

FN1A ~ FN4A

FN1B ~ FN4B

Fan1B~Fan4B magnet contactors

OLC1

OLF1A ~ OLF4A

OLF1B ~ OLF4B

Fan1B~Fan4B over current relays

Power indicator lamp

Emergency switch

SW1

Low pressure switch

Reverse phase protector

High pressure switch

Mold option switch

RCAW090PBAA

Page 78

Appendix

78 Chiller Air-cooled Screw

n Cycle Diagram

Fig. 49

DESCRIPTION

Compressor

Condensing coil

Receiver

Oil Filter

Oil separater

Ejector for Oil Return

Expansion Devices

7,8

Filter Drier

Evaporator

SYMBOL

Oil heater

High pressure switch

LEGEND

DESCRIPTION

HPS

LPS

Low pressure switch

Temperature sensor

Oil level sensor

OLS

Oil flow switch

OFS

Water flow switch

Relief valve

WFS

AFS

Anti-freezing switch

Insulation

Oil sol. valve

Sight glass

Refrigerant sol. valve

Economizer (Flash gas tank)

Check valve

Service valve

Oil Pipe Line

Low Pressure Line

High Pressue Line

Liquid Injection Line

HPS

AFS

LPS

WFS

OFS

OLS

Pipe line

RCAW090,100

Page 79

Appendix

Operation & Maintenance Manual 79

n Check List

1. Project information

2. Model information

Checklist for installation, and operation

Contents Description

PJT name

Address

Installing contractor

Sales office

Start-up performer

Contents Description

PJT name

Address

Installing contractor

Sales office

Start-up performer

Contents Description

Unit

Model: Serial:

Compressor A

Model: Serial:

Compressor B

Model: Serial:

Page 80

Appendix

80 Chiller Air-cooled Screw

3. PRELIMINARY EQUIPMENT CHECK

4. Chilled Water System Check

CheckContents

NoYesDrain pipe is not clogged.

NoYesInlet piping to cooler includes strainer.

NoYesChilled water flow switch is operational.

NoYesChilled water pump starter interlocked with chiller.

NoYesChilled water pump is operating with the correct rotation.

NoYesAll air has been purged from the system.

NoYesThere is no leakage.

YesAll piping is connected properly.

YesAll chilled water valves are open.

CheckContents

Is there any physical damage? Yes No

ơ If yes, where?

Will this prevent start-up. Yes No

All screws and bolts are tight. Yes No

Power supply agrees with the unit nameplate. Yes No

Electrical power wiring is installed properly. Yes No

Unit is properly grounded. Yes No

Electrical circuit protection has been sized and installed properly. Yes No

All terminals are tight. Yes No

All plug assemblies are tight. Yes No

Oil heaters energized for 8 hours before start-up. Yes No

Relief valve vents piping per local codes. Yes No

Page 81

Appendix

Operation & Maintenance Manual 81

5. START-UP & OPERATION

Ambient air temperature

Compressor capacity

psigCooler pressure drop

psigRefrigerant high pressure

psigRefrigerant low pressure

lbsAdditional refrigerant charge

Gpm(l/s)Chilled water flow rate

Chilled water inlet temperature

%Brine concentration

NoYesThere is no abnormal noise or vibration

lbsAdditional oil charge

Chilled water inlet temperature

NoYesAlarm is not generated, and the unit operates normally.

NoYes

Voltage imbalance is within 2%

NoYes

Voltage at terminal block is within 10%

Yes

There is leakage of refrigerant. (Comp, Condenser, Economizer, Cooler…)

Yes

All refrigerant line service valves are open. (discharge, suction, economizer, oil line part…)

CheckContents

Page 82

P/No.: MFL63291701

Printed in Korea

After reading this manual, keep it in a place easily accessible to the user for future reference.

LG RCAW Operation & Maintenance Manual

Specifications and Main Features

Frequently Asked Questions

User Manual