LG LWC121CGMK0 User manual

LG Room
Air Conditioner
SERVICE MANUAL
LG
MODELS: LWC121CGMK0
LWC143CGMK0
LWC143CSMK0
LWC243NSAB1
LWC243NSMM1
CAUTION
website http://www.lgservice.com
• BEFORE SERVICING THE UNIT, READ THE SAFETY
PRECAUTIONS IN THIS MANUAL.
• ONLY FOR AUTHORIZED SERVICE PERSONNEL.

2Room Air Conditioner
Air Conditioner Service Manual
TABLE OF CONTENTS
Safety Precautions..........................................................................................................................................3
Dimensions .....................................................................................................................................................7
Outside Dimensions...................................................................................................................................7
Product Specifications ................................................................................................................................11
Installation.....................................................................................................................................................11
Select the Best Location .........................................................................................................................11
Installation Check.....................................................................................................................................11
How to Secure the Drain Pipe..................................................................................................................11
How to Install(Installation kit not included models)...................................................................................12
How to Install(Installation kit included models).........................................................................................13
When Using Installation Kits ....................................................................................................................13
Suggested Tool Requirements.................................................................................................................14
Operation ......................................................................................................................................................17
Features...................................................................................................................................................17
Function of Controls.................................................................................................................................17
Disassembly..................................................................................................................................................20
Mechanical Parts......................................................................................................................................20
Air Handling Parts ....................................................................................................................................21
Electrical Parts.........................................................................................................................................22
Refrigerating Parts ...................................................................................................................................24
Schematic Diagram.......................................................................................................................................27
Electronic Control Device.........................................................................................................................27
Wiring Diagram.........................................................................................................................................28
Components Location ..............................................................................................................................29
Troubleshooting Guide.................................................................................................................................30
Piping System ..........................................................................................................................................30
Troubleshooting Guide .............................................................................................................................31
Room Air Conditioner Voltage Limits........................................................................................................33
Exploded View ..............................................................................................................................................35
Replacement Parts List ................................................................................................................................37

Service Manual 3
Safety Precautions
Safety Precautions
To prevent injury to the user or other people and property damage, the following instructions must
be followed.
■Incorrect operation due to ignoring instruction will cause harm or damage. The seriousness is
classified by the following indications.
■Meanings of symbols used in this manual are as shown below.
WARNING
CAUTION
This symbol indicates the possibility of death or serious injury.
This symbol indicates the possibility of injury or damage to property only.
WARNING
■Installation
Always install the expansion panel(s).
• No installation may cause fire and electric shock acci-
dent.
Do not place the power cord near a heater.
• It may cause fire and electric shock.
Do not use the power cord near flammable gas
or combustibles such as gasoline, benzene,
thinner, etc.
• It may cause explosion or fire.
Do not disassemble or modify products.
• It may cause failure and electric shock.
Be sure not to do.
Be sure to follow the instruction.
Gasolin

4Room Air Conditioner
Safety Precautions
■Operational
Plug in the power plug proper-
ly.
• Otherwise, it will cause electric
shock or fire due to heat generation
or electric shock.
Do not operate or stop the
unit by inserting or pulling out
the power plug.
• It will cause electric shock or fire
due to heat generation.
Do not damage or use an
unspecified power cord.
• It will cause electric shock or fire.
Do not modify power cord
length.
• It will cause electric shock or fire
due to heat generation.
Do not share the outlet with
other appliances.
• It will cause electric shock or fire
due to heat generation.
Always plug into a grounded
outlet.
• No grounding may cause electric
shock (See Installation Manual).
Unplug the unit if strange
sounds, odors, or smoke
come from it.
• Otherwise it may cause fire and
electric shock accident.
Do not use the socket if it is
loose or damaged.
• It may cause fire and electric
shock.
Do not operate with wet hands
or in damp environment.
• It will cause electric shock.
ON

Service Manual 5
Safety Precautions
CAUTION
■Installation
Do not allow water to run into
electric parts.
• It will cause failure of machine or
electric shock.
Leave the door closed while
the air conditioner is running.
• It is not designed to cool the entire
house.
Ventilate before operating air
conditioner when gas goes
out.
• It may cause explosion, fire, and
burn.
Never touch the metal parts
of the unit when removing the
filter.
• They are sharp and may cause
injury.
Do not block the inlet or out-
let.
• It may cause failure of appliance or
accident.
Ensure that the outer case is
not damaged by age or wear.
• If leaving appliance damaged,
there is concern of damage due to
the falling of product.
Be cautious not to touch the
sharp edges when installing.
• It may cause injury.
Hold the plug by the head
when taking it out.
• It may cause electric shock and
damage.
Turn off the main power
switch when not using it for a
long time.
• Prevent accidental startup and the
possibility of injury.
Sharp
edges

6Room Air Conditioner
Safety Precautions
Do not place heavy object on
the power cord and take care
so that the cord should not be
pressed.
•There is danger of fire or electric
shock.
If water enters the product, turn
off the the power switch of the
main body of appliance. Contact
service center after taking the
power-plug out from the socket.
Do not clean the air
conditioner with water.
•Water may enter the unit and
degrade the insulation. It may
cause an electric shock.
Turn off the power and break-
er firstly when cleansing the
unit.
•Since the fan rotates at high speed
during operation, it may cause
injury.
Do not put a pet or house
plant where it will be exposed
to direct air flow.
•This could injure the pet or plant.
Do not use this appliance for
special purposes such as
pets, foods, precision
machinery, or objects of art.
•It is an air conditioner, not a preci-
sion refrigeration system.
Always insert the filter
securely.
Clean it every two weeks.
•Operation without filters will cause
failure.
Use a soft cloth to clean. Do
not use wax, thinner, or a
strong detergent.
•The appearance of the air condi-
tioner may deteriorate, change
color, or develop surface flaws.
Do not drink water drained
from air conditioner. / Do not
direct airflow at room
occupants only.
•It contains containments and will
make you sick. / This could dam-
age your health.
Wax
Thinner

Service Manual 7
Dimensions
Dimensions
H
W
D
W mm(inch) 600(23 5/8)
H mm(inch) 380(14 31/32)
D mm(inch) 567(22 5/16)
Model
Dimension
12K , 14K MODELS
D mm(inch) 560(22 5/16") 555(21 6/7")
Look
Dimension
G/P/E N
Outside Dimensions
This symbol alerts you to the risk of electric shock.
This symbol alerts you to hazards that could cause harm to the
air conditioner.
This symbol indicates special notes.
NOTICE
Symbols Used in this Manual

8Room Air Conditioner
DW
H
W mm(inch) 660(26")
H mm(inch) 428(16 27/32")
D mm(inch) 675(269/18")
Model
Dimension
24K Btu
Dimensions

Service Manual 9
Product Specifications
* DB:Dry Bulb
** WB:Wet Bulb
NOTE: Please refer to Label Quality on the produst since this specification may be changed for improving performance.
LWC121CGMK0 LWC143CGMK0
LWC143CSMK0
POWER SUPPLY
COOLING CAPACITY (Btu/h)
INPUT (W)
RUNNING CURRENT (A)
E.E.R (BTU/W.h)
OPERATING
INDOOR (°C)
CONDITION
OUTDOOR (°C)
REFRIGERANT (R-22) CHARGE
EVAPORATOR
CONDENSER
FAN, INDOOR
FAN, OUTDOOR
FAN SPEEDS, FAN/COOLING
FAN MOTOR
OPERATION CONTROL
ROOM TEMP. CONTROL
AIR DIRECTION CONTROL
CONSTRUCTION
PROTECTOR COMPRESSOR
FAN MOTOR
POWER CORD
DRAIN SYSTEM
NET WEIGHT (lbs/kg)
OUTSIDE DIMENSION (inch)
(WxHxD) (mm)
1Ø,115V,60Hz 1Ø,220V,60Hz
12,000 14,000
1,220 1,400
11 6.2
9.8 10
26.7(DB),19.4(WB)
35(DB),23.9(WB)
355g(12.5oz) 670g(23.6oz)
2 ROW 16STACKS 2 ROW 13STACKS
2 ROW 18STACKS 2 ROW 14STACKS
TURBO
PROPELLER TYPE FAN WITH SLINGER-RING
3/3
6 POLES
REMOTE CONTROLLER
THERMISTOR
VERTICAL LOUVER(RIGHT&LEFT)
HORIZONTAL LOUVER (UP&DOWN)
SLIDE IN-OUT CHASSIS
OVERLOAD PROTECTOR
INTERNAL THERMAL PROTECTOR
(3 WIRE WITH GROUNDING)
ATTACHMENT PLUG (CORD-CONNECTED TYPE)
DRAIN PIPE OR SPLASHED BY FAN SLINGER
95/43
235/8x14
31/32 x22 5/16
600 x 380 x 567
MODELS
ITEMS
Specfications

10 Room Air Conditioner
Specfications
* DB:Dry Bulb
**
WB:Wet Bulb
NOTE: Please refer to Label Quality on the produst since this specification may be changed for improving performance.
LWC243NAB1 LWC243NSMM1
POWER SUPPLY
COOLING CAPACITY (Btu/h)
INPUT (W)
RUNNING CURRENT (A)
E.E.R (BTU/W.h)
OPERATING
INDOOR (°C)
CONDITION
OUTDOOR (°C)
REFRIGERANT (R-22) CHARGE
EVAPORATOR
CONDENSER
FAN, INDOOR
FAN, OUTDOOR
FAN SPEEDS, FAN/COOLING
FAN MOTOR
OPERATION CONTROL
ROOM TEMP. CONTROL
AIR DIRECTION CONTROL
CONSTRUCTION
PROTECTOR COMPRESSOR
FAN MOTOR
POWER CORD
DRAIN SYSTEM
NET WEIGHT (lbs/kg)
OUTSIDE DIMENSION (inch)
(W x H x D) (mm)
1Ø,220V,60Hz
24,000
2,820
12.9
8.5
26.7(DB),19.4(WB)
35(DB),23.9(WB)
985g(34.8oz)
3 ROW 15STACKS
2 ROW 19STACKS
TURBO
PROPELLER TYPE FAN WITH SLINGER-RING
2/3 3/3
6 POLES
ROTARY SWITCH REMOTE CONTROLLER
THERMISTOR THERMISTOR
VERTICAL LOUVER(RIGHT&LEFT)
HORIZONTAL LOUVER (UP&DOWN)
SLIDE IN-OUT CHASSIS
OVERLOAD PROTECTOR
INTERNAL THERMAL PROTECTOR
(3 WIRE WITH GROUNDING)
ATTACHMENT PLUG (CORD-CONNECTED TYPE)
DRAIN PIPE OR SPLASHED BY FAN SLINGER
146/66
265/8x16
27/32 x26 9/18
660 x 428 x 675
MODELS
ITEMS

Service Manual 11
Installation
Installation
Select the Best Location
Installation Check
How to Secure the Drain Pipe(When using drain pipe)
1.To prevent vibration and noise, make sure the unit is
installed securely and firmly.
2.Install the unit where the sunlight does not shine directly
on the unit.
3.The outside of the cabinet must extend outward for at
least 12" and there should be no obstacles, such as a
fence or wall, within 20" from the back of the cabinet
because it will prevent heat radiation of the condenser.
Restriction of outside air will greatly reduce the cooling
efficiency of the air conditioner.
CAUTION: All side louvers of the cabinet
must remain exposed to the outside of
the structure.
4.Install the unit a little slanted so the back is slightly lower
than the front (about 1/2"). This will help force condensed
water to the outside.
5.Install the unit from the bottom about 30"~60" above the
floor level.
The setting conditions must be checked prior to initial starting.
The following items are especially important check points when the installation is finished.
1. Grounding wire (Green or Green and Yellow) is provided in the power cord. The green wire must be grounded.
2. Connect to a single-outlet 15A circuit.
(or 20A circuit for Electric Heater Model)
3. To avoid vibration or noise, make sure the air conditioner is installed securely.
4 Avoid placing furniture or draperies in front of the air inlet and outlet.
In humid weather, excess water may cause the BASE PAN to overflow. To drain
the water, remove the DRAIN CAP and secure the DRAIN PIPE to the rear hole of
the BASE PAN. Press the drain pipe into the hole by pushing down and away from
the fins to avoid injury.
Optional
1. Install the drain pan over the corner of the cabinet where you removed the
plug with 4 (or 2) screws.
2. Connect the drain hose to the outlet located at the bottom of the drain pan.
You can purchase the drain hose or tubing locally to satisfy your particular
needs. (Drain hose is not supplied).
3. Select the most appropriate connection from among the following figures (by
considering the hole of the unit) to fit drain pan to your own unit.
AWNING
COOLED AIR HEAT
RADIATION
30"~60"
ABOUT 1/2"
Over 20"
FENCE
Drain pipe
Drain cap
Fig. 4
Fig. 3
Fig. 2
DRAIN
PAN DRAIN HOSE
Fig. 1
CABINET SCREW
Figure 1

12 Room Air Conditioner
Installation
How to Install (Models without Installation kit)
1. Remove the screws which fasten the cabinet
at both sides and at the back.
2. Slide the unit from the cabinet by gripping
the base pan handle and pulling forward
while bracing the cabinet.
3. Remove EPS Material.
4. Slide the unit into the cabinet.
CAUTION: For security pur-
pose, reinstall screw at cabi-
net's sides.
5. Attach the front grille to the cabinet by
inserting the tabs on the grille into the tabs
on the fornt of the cabinet. Push the grille in
until it snaps into place.
6. Lift the inlet grille and secure it with a screw
through the front grille.
Shipping screws
EPS Material
Power cord
Screw
Screw
• For MODELS : LWC121CGMK0 / LWC143CGMK0

Service Manual 13
Installation
How to Install (Models with Installaion Kit )
When Using Gasket
When Using Installation Kits
1. Window Requirements
This unit is designed for installation in
standard double hung windows with actual opening
widths from 27" to 39".
The top and bottom window sash must open suffi-
ciently to allow a clear vertical opening of 16" from the
bottom of the upper sash to the window stool.
2. Installation Kits Contents
A
B
DE
F
H
2
31
4
2
1A
RIGHT SIDE
HORIZONTAL
LINE
B
1. WINDOW (WIDTH-A, HEIGHT-B)
2. GASKET
3. WALL
4. DETAILS 5.1 x 30 ROUND HEAD WOOD
SCREWS
ABCDE F HI
625mm 392mm 280mm 30mm 0~25mm OVER 420mm 5~10mm -5~5mm
(245/8") (157/16") (111/32") (11/16") (0~1") (OVER 1617/32") (3/16"~3/8") (-3/16"~3/16")
27" to 39"
16" min Stool
Interior wall
235/8" min
(Without frame curtain)
Offset
1/2" to 11/4"
Sill
Exterior
12 3 4
811
12
9
765
10
■Top retainer bar is in
the product package.
NO. NAME OF PARTS Q'TY
1 FRAME CURTAIN 2
2 SILL SUPPORT 2
3BOLT 2
4 NUT 2
5 SCREW(TYPE A) (10mm(2/5")) 16
6 SCREW(TYPE B) D5.1mm(0.2")/16mm(0.63") 3
7 SCREW(TYPE C) D4.1mm(0.17")/16mm(0.63") 5
8FOAM-STRIP 1
9 FOAM-PE (600mm x 25mm x 2mm) 1
10 WINDOW LOCKING BRACKET 1
11 FOAM-PE (920mm x 30mm x 2mm) 1
12 DRAIN PIPE 1

14 Room Air Conditioner
Suggested Tool Requirements
SCREWDRIVER(+, -), RULER, KNIFE, HAMMER, PENCIL, LEVEL
Preparation of Chassis
1. Remove the screws which fasten the cabinet at
both sides and at the back.
2. Slide the unit out from the cabinet by gripping the
base pan handle and pulling forward while
bracing the cabinet.
3. Remove EPS Material.
4. Cut the window sash seal to the proper length. Peel
off the backing and attach the foam-pe to the
underside of the window sash.
5. Remove the backing from the top upper guide
Foam PE and attach it to the bottom of the upper
guide .
6. Attach the upper guide onto the top of the cabinet
with 3 type A screws.
7. Insert the frame guides into the bottom of the
cabinet.
8. Insert the Frame Curtain into the upper guide
and frame guides .
9. Fasten the curtains to the unit with 4 Type A screws
at the both sides.
Cabinet Installation
1. Open the window. Mark a line on center of the win-
dow stool(or desired air conditioner location).
Carefully place the cabinet on the window stool and
align the center mark on the bottom front with the
center line marked in the window stool.
2. Pull the bottom window sash down behind the
upper guide until it meets.
Do not pull the window sash down so
tightly that the movement of Frame
Curtain is restricted.
NOTICE
EPS Material
9
10
11
10
5
5
5
12
12
(Type A)
(Type A)
Upper Guide
Front Angle Window stool
Upper guide
Window Sash
Cabinet
Frame Curtain
10
1
Shipping screws
Figure 2
Figure 3
Installation

Service Manual 15
INDOOR OUTDOOR
Sill Support
Nut
Bolt
2
4
3
INDOOR OUTDOOR
12
6
7
2
5
Frame Guide
About 1/2"
Screw(Type A)
Cabinet
6
2
About 1/2"
Screw(Type B) 5 Screw(Type A)
Sill support
Sash track
Front Angle
Type C
Screw(Type B)
Sill support
3. Loosely assemble the sill support using the parts
in Figure 4.
4. Select the position that will place the sill
support near the outer most point on sill
(See Figure 4)
Be careful when you install the cabinet
(Frame Guides are broken easily).
5. Attach the sill support to the cabinet track hole in
relation to the selected position using
2 Type A screws in each support (See Figure 5).
6. The cabinet should be installed with a very slight
tilt (about 1/2") downward toward the outside
(See Figure 6).
Adjust the bolt and the nut of Sill Support for bal-
ancing the cabinet.
7. Attach the cabinet to the window stool by
driving the screws (Type B) through the front
angle into window stool (5/8").
8. Pull each Frame Curtain properly to each window
sash track, and repeat step 2.
9. Attach each Frame Curtain to the window sash by
using screws (Type C).(See Figure 7)
NOTICE
Figure 4
Figure 5
Figure 6
Figure 7
Installation

16 Room Air Conditioner
Installation
13
8
Foam-Strip
Screw(Type A)
Screw(Type A)
Power cord
10. Slide the unit into the cabinet.(See Fig. 8)
CAUTION:
For security purpose, reinstall
screws (Type A) at the cabinet's sides.
11. Cut the Foam-Strip to the proper length and insert
between the upper and lower window sash.
(See Fig. 9)
12. Attach the window Locking Bracket with a type C
screw. (See Fig. 10)
13. Attach the front grille to the cabinet by inserting the
tabs on the grille into the tabs on the front of the cab-
inet. Push the grille in until it snaps into place.
(See Fig. 11)
14. Lift the inlet grille and secure it with a type A screw
through the front grille.(See Fig. 12)
Figure 11
Figure 8
Figure 9
Figure 10
Figure 13
Figure 12

•Designed for COOLING ONLY.
•Powerful and quiet cooling.
•Slide-in and slide-out chassis for the simple instal-
lation and service.
•Side air-intake, side cooled-air discharge.
•VENTILATION
The ventilation lever must be in the CLOSE position
in order to maintain the best cooling conditions.
When a fresh air is necessary in the room, set the
ventilation lever OPEN position.
The damper is opened and room air is exhausted.
•THERMOSTAT
Thermostat will automatically control the temperature
of the room. Select a higher number for a cooler tem-
perature in the room. The temperature is selected by
positioning the knob to the desired position.
The 5or 6position is a normal setting for average
conditions.
•Built-in adjustable THERMOSTAT
•Washable one-touch filter
•Compact size
• Equipped with reliable and efficient rotary compressor.
Service Manual 17
Operation
Operation
Features
Control Locations Function of Controls
CLOSE VENT OPEN
•Operation
Off - Turns air conditioner off.
Med Fan - Med speed fan operation without cooling.
Low Fan - Low speed fan operation without cooling.
High Cool - Cooling with high speed fan operation.
Med Cool - Cooling with med speed fan operation.
Low Cool - Cooling with low speed fan operation.
•For Normal Cooling
1. Turn the Operation Knob to the High Cool from the Low
Cool setting.
2. Set the Thermostat control to the desired temperature
mark 5(the mid-point is a good starting position). If the
room temperature is not satisfactory after a reasonable
time, adjust the control to a cooler or warmer setting, as
appropriate.
•For Maximum Cooling
1. Turn the Operation Knob to the High Cool setting.
2. Set the Thermostat control to the 9temperature mark.
•For Quieter Operation
1. Turn the Operation Knob to the Low Cool setting.
2. Set the Thermostat control as needed.
CAUTION: When the air conditioner has completed its cooling operation and is
turned off or set to the fan position, wait at least 3 minutes before resetting to the
cooling operation again.

Operation
18 Room Air Conditioner
Power
Temp
Fan Speed
Timer Mode
Energy
Saver
1
4
2
6
3
5
1
6
54
2 3
7
CAUTION: When the air conditioner has completed its cooling operation and is
turned off or set to the fan position, wait at least 3 minutes before resetting to the
cooling operation again.
1. POWER BUTTON
To turn the air conditioner ON, push the button. To turn the air conditioner OFF, push the button again.
This button takes priority over any other buttons.
2. OPERATION MODE SELECTION BUTTON
Everytime you push this button, it will toggle COOL, FAN and DRY.
3. ON/OFF TIMER BUTTON
Everytime you push this button, timer is set as follows.(1Hour ➔2Hours ➔3Hours ➔4Hours ➔5Hours ➔
6Hours ➔7Hours ➔8Hours ➔9Hours ➔10Hours ➔11Hours ➔12Hours ➔Cancel)
4. FAN SPEED SELECTOR
Everytime you push this button, it is set as follows. (Hi[ F3 ]➔Low[ F1 ]➔Med[ F2 ]➔Hi[ F3 ]....)
5. ROOM TEMPERATURE SETTING BUTTON
This button can automatically control the temperature of the room. The temperature can be set within a range
of 60°Fto86°Fby1°F.
Select the lower number for lower temperature of the room.
6. ENERGY SAVER
The fan stops when the compressor stops cooling.
Approximately every 3 munutes the fan will turn on and check the room air to determine if cooling is needed.
7. REMOCON SIGNAL RECEIVER

Service Manual 19
Operation
4
3
6
2
5
1
1
7
3 24
5 6
1. POWER BUTTON
Operation starts, when this button is pressed and stops when you press the button again.
2. AUTO SWING (Optional)
The vertical louver swings horizontally by the automatic system and stops when you press the button again.
3. ROOM TEMPERATURE SETTING BUTTON
Control the room temperature within a range of 16°Cto30°C.
4. FAN SPEED SELECTOR
Select the fan speed in three steps {High[F3] →Low[F1] →Med[F2] →High[F3]...}.
5. OPERATION MODE SELECTION BUTTON
Select Cooling, Fan, or Dehumidification mode with this button.
6. ON/OFF TIMER BUTTON
Set the time of starting and stopping operation. The timer is set by 1 hour.
7. SIGNAL RECEIVER
•For MODELS : LWC243NSMM1

20 Room Air Conditioner
Disassembly
Disassembly
Mechanical Parts
—Before disassembly, set the CONTROL BOX to OFF and disconnect the power cord.
1. Front Grille
1. Open the lnlet grille upward .
2. Remove the screw which fastens the front grille.
3. Pull the front grille from the right side.
4. Remove the front grille.
5. Re-install the component by referring to the removal
procedure, above.(See Figure 14)
2. Cabinet
1. After disassembling the FRONT GRILLE, remove the
2 screws which fasten the cabinet at both sides.
2. Remove the 2 screws which fasten the cabinet at
back.
3. Pull the base pan forward. (See Figure 15)
4. Remove the cabinet.
5. Re-install the component by referring to the removal
procedure, above.
3. Control Box
1. Remove the front grille. (Refer to section 1)
2. Remove the cabinet. (Refer to section 2)
3. Remove the 2 screws which fasten the control box
cover.
4. Remove two housings which connect compressor
wire and motor wire in the control box.
5.Discharge the capacitor by placing a 20,000 ohmresis-
tor across the capacitor terminals.
6. Remove the 2 screws which fasten the control box.
7. Pull the control box forward completely.
8. Re-install the components by referring to the removal
procedure, above. (See Figure 16)
(Refer to the circuit diagram found on page 23 in this
manual and on the control box.)
2
3
4
8
7
6
5
Off
Med
FanHigh
Cool
Figure 14
Figure 16
Figure 15