LG RCAW090PBAA Owner's manual

Type
Owner's manual
Operation & Maintenance Manual
LG
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
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
Safety Considerations
Operation & Maintenance Manual 3
Installing, starting up, and servicing this equipment can be hazardous due to system pressures, electrical com-
ponents, 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 pre-
cautions in the literature, and on tags, stickers, and labels attached to the equipment, and any other safety pre-
cautions 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.
â–  Incorrect operation due to ignoring Instructions in the manual will cause harm or damage. The seriousness is
classified by the following indications.
â–  We do not have any responsibility for any failure caused by careless management and natural disaster, and
power cord failure regardless of warranty period.
â–  The content in the manual could be changed for the improvement of product without notice.
â–  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 elec-
trician 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
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 spec-
ified on the unit.
• If a different refrigerant or air is mixed with the
original refrigerant, the refrigerant cycle may mal-
function 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, mea-
sures 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.
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 pro-
hibited.
• 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 refrig-
erant, 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, cool-
ing 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 earth-
quake, or risk of lightning, immediately stop oper-
ating the unit.
• If you continue to operate the unit, it can cause a
fire or electric shock.
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 val-
ues, 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 pre-
cautions 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 equip-
ment, 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 tub-
ing cutter as required when performing ser-
vice.
• Compressor oil is flammable and there is no way
to detect how much oil may be in any of the refrig-
erant 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.
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 refriger-
ation 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, commu-
nication station, or similar place, provide suffi-
cient protection against noise.
•
The inverter equipment, private power generator, high-
frequency medical equipment, or radio communication
equipment may cause the chiller to operate erroneous-
ly, 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 opera-
tion.
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 gener-
ate heat and cause a fire.
Be sure the installation area does not deterio-
rate with age.
• If the base collapses, the chiller could fall with it,
causing property damage, product failure, or per-
sonal 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 dur-
ing 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.
Safety Considerations
Operation & Maintenance Manual 9
Be careful of disposal.
• When disposing the device, request to the spe-
cialized 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 sur-
rounding 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.
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 per-
formance and reduce the potential of tubing damage
due to corrosion, scaling, erosion, and algae.
• LG assumes no responsibility for chiller or con-
denser 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 consump-
tion.
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 con-
trols.
• This ensures safety and prevents damage to con-
troller.
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.
â–  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 sec-
onds. 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
LG
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
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 com-
pressor 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 tem-
perature (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 initial-
ized.
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
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 dur-
ing 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
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
General
14 Chiller Air-cooled Screw
Compressor shutdown temperature means the temperature where the compressor must be shut downed by low temper-
ature. Here, the default value is 5.0°C(41°F). Compressor restart temperature means the temperature where the com-
pressor must restart after shutdown. Here the default value is 12°C(53.6°F). By difference between the shutdown tem-
perature 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 con-
sequently, 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.
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 pres-
sure 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
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
3
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
OFF
Fig. 4
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 com-
pressor runs. The switch opens when the differential pressure between condenser and evaporator is lower than the set-
ting 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 consid-
ers 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 topolo-
gy. 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
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
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 adjust-
ed 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
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
2.0 °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 oper-
ations 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 anti-
freezing switch shown in I/O display.
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
SET
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 com-
pressor 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, dis-
charge temp means the delay for the determination of high compressor discharge temperature alarm.
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LG RCAW090PBAA Owner's manual

Type
Owner's manual

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