LG ARWN038GA2 User manual

System
Outside Unit
SERVICE MANUAL R410A
MODEL : WATER MINI Series
CAUTION
Before Servicing the units, read the safety precautions in General SVC manual.
Only for authorized service personnel.
Internal Use Only
http://biz.lgservice.com
R410A

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Air Conditioner Service Manual
TABLE OF CONTENTS
Safety Precautions .....................................................................................................3
Part 1 General Information ......................................................................................10
Model Names .............................................................................................................................11
External Appearance..................................................................................................................11
Nomenclature .............................................................................................................................12
Part 2 Outside Units .................................................................................................................13
Part 3 Test Run ..........................................................................................................................28
Part 4 Trouble Shooting Guide.............................................................................................34

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
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 properties only.
Be sure not to do.
Be sure to follow the instruction.
WARNING
■Installation
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 air conditioner.
• Improper installation by the user may result in
water leakage, electric shock, or fire.
Always ground the product.
• There is risk of fire or electric shock.
Always intstall a dedicated circuit and breaker.
• Improper wiring or installation may cause fire or
electric shock.

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Safety Precautions
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 air conditioner.
• There is risk of fire or failure of product.
Use the correctly rated breaker or fuse.
• There is risk of fire or electric shock.
Prepare for strong wind or earthquake and
install the unit at the specified place.
• Improper installation may cause the unit to top-
ple and result in injury.
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 air condition-
er 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.
Gasolin
R22
R407C
R410A

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
■Operation
Safety Precautions
Ventilate before operating air conditioner
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 outside unit and fire
or electric shock may result.
If the air conditioner 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 exceed-
ed. Should the refrigerant leak and cause the safety limit to be exceeded, harzards due to lack of oxy-
gen in the room could result.
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.

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
CAUTION
■Installation
Safety Precautions
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 outside unit.
• This could result in personal injury and product
damage.
Do not open the inlet grille of the product during operation. (Do not touch the electrostatic fil-
ter, if the unit is so equipped.)
• There is risk of physical injury, electric shock, or product failure.
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 outside 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.
90˚
Gasolin

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Safety Precautions
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 air conditioner, not a precision
refrigeration system.
• There is risk of damage or loss of property.
When installting the unit in a hospital, com-
munication station, or similar place, provide
sufficient protection against noise.
•
The inverter equipment, private power generator,
high-frequency medical equipment, or radio com-
munication equipment may cause the air condition-
er to operate erroneously, or fail to operate. On the
other hand, the air conditioner 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, particularly on the condenser and
evaporator fins, could cause product malfunction
or inefficient operation.
■Operation
Do not use the air conditioner in special
environments.
• Oil, steam, sulfuric smoke, etc. can significantly
reduce the performance of the air conditioner or
damage its parts.
Do not block the inlet or outlet.
• It may cause failure of appliance or accident.

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Safety Precautions
Make the connections securely so that the
outside force of the cable may not be applied
to the terminals.
• Inadequate connection and fastening may gen-
erate heat and cause a fire.
Be sure the installation area does not deteri-
orate with age.
• If the base collapses, the air conditioner could
fall with it, causing property damage, product
failure, or personal injury.
Install and insulate the drain hose to ensure
that water is drained away properly based on
the installation manual.
• A bad connection may cause water leakage.
Be very careful about product transportation.
• Only one person should not carry the product if it
weighs more than 20kg.
• Some products use PP bands for packaging.
Do not use any PP bands for a means of trans-
portation. It is dangerous.
• Do not touch the heat exchanger fins.
Doing so may cut your fingers.
• When transporting the outside unit, suspending
it at the specified positions on the unit base.
Also support the outside unit at four points so
that it cannot slip sideways.
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.

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Safety Precautions
Turn on the power at least 6 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 air conditioner 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.
• Wait at least 5minutes before turning off the
main power switch. Otherwise it may result in
water leakage or other problems.
Auto-addressing should be done in condition of
connecting the power of all indoor and outdoour
units. Auto-addressing should also be done in
case of changing the indoor unit PCB.
Use a firm stool or ladder when cleaning or
maintaining the air conditioner.
• Be careful and avoid personal injury.
Do not insert hands or other objects through the air inlet or outlet while the air conditioner is
plugged in.
• There are sharp and moving parts that could cause personal injury.

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Part 1
General Information
1. Model Names .................................................................11
1.1 Indoor Unit...............................................................11
2. External Appearance .....................................................11
2.1 Outside Unit.............................................................11
3. Nomenclature.................................................................12

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
1. Model Names
Model Names
1.1 Outside Unit
Power Supply 4HP 5HP 6HP
1Ø, 208/230V, 60Hz 038GA2 048GA2 053GA2
Heat Pump ARWN
2.1 Outside Unit
2. External Appearance
• 1Ø
ARWN038GA2
ARWN048GA2
ARWN053GA2

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Nomenclature
3. Nomenclature
Generation
Air Discharge Type
A : Basic
Electrical Ratings
G : 1Φ, 220/240V, 50Hz / 1Φ, 208/230V, 60Hz
Total Cooling Capacity in Btu/h
EX) ‘038’ → 38,000Btu/h Class
Combination of Inverter Type and
Cooling Only or Heat Pump
N: Inverter and H/P
Indicates that this is Water System
Outside Unit using the R410A
ARW N G038 A2
3.1 Outside Unit

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Part 2
Outside Unit

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
• Function ........................................................................................15
Water Mini Series

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
Function
1. Basic control ...................................................................................................................16
1.1 Normal operation .......................................................................................................16
1.2 Compressor control....................................................................................................16
1.3 Master and slave unit's EEV control ..........................................................................17
2. Special control ................................................................................................................18
2.1 Oil return control ........................................................................................................18
2.2 Stopping operation.....................................................................................................20
3. Protection control ...........................................................................................................21
3.1 Pressure protection control ........................................................................................21
3.2 Discharge temperature control...................................................................................22
3.3 Inverter protection control ..........................................................................................22
3.4 Liquid back control .....................................................................................................23
3.5 Pressure switch..........................................................................................................23
4. Other control ...................................................................................................................24
4.1 Initial setup.................................................................................................................24
4.2 Vacuum Mode ............................................................................................................26
4.3 Black Box Function ....................................................................................................27
Function

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
1. Basic control
Function
1.2 Compressor control
Fuzzy control : Maintain evaporating temperature(Te) to be constant on cooling mode and condensing tem-
perature(Tc) on heating mode by Fuzzy control to ensure the stable system performance.
(Tc:47 ~ 51°C (117 ~ 124°F), Te:2 ~ 5°C (36 ~41°F))
(1) Cooling mode
Te can be set by initial DIP switch setting. (Standard, Long pipe)
(2) Heating mode
Tc can be set by initial DIP switch setting. (Standard, Long pipe)
Note: By setting DIP switch, Te and Tc are decided simultaneously.
1.1 Normal operation
Compressor
Main EEV
4 way valve
Fuzzy control
Full open
OFF OFF
Fuzzy control
Fuzzy control
ON
Cooling operation Heating operationActuator
Stop
Close
Stop state
Fuzzy Control
Stop
Set frequency
Fuzzy control start
Target
Inverter linear control as cooling and heating load increasing
System Capacity
Cooling and heating load
(Linear Control)(Linear Control)(Linear Control)
InverterInverter
CompressorCompressor
Inverter
Compressor

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
1.3 EEV control
(1) EEV control
EEV operates with fuzzy control rules to keep the degree of super Heat (about 3°C)at the evaporator out-
let stable during heating mode
The degree of Superheat = Tsuction - Tevaporation
Tsuction : temperature at suction pipe sensor (°C/°F)
Tevaporation : evaporation temperature equivalent to low pressure (°C/°F)
Function

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
2.1 Oil return control
2.1.1 Oil return control on cooling mode
Oil return operation recovers oil amount in compressor by collecting oil accumulated in pipe.
Each cycle component operates as following table during oil return operation.
■Oil return operation time : 3min for running step
■Starting condition:every 3hours operate
■Oil return process ends if compressor protection control starts
Normal control
OFF
Max. pulse
40Hz
Ending
Normal control
OFF
Max. pulse
Setting Value
Running
Normal control
OFF
Max. pulse
25Hz
Starting
Hot gas bypass valve
4way valve
Main EEV
Inv Compressor
Component
OFF
Min. pulse
Normal control
Ending
ON
1200 pulse
1200 pulse
Running
OFF
Min. pulse
Normal control
Starting
Oil return signal
Thermo off unit EEV
Thermo on unit EEV
Component
Outside Unit
Indoor Unit
2. Special control
Function

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
2.1.2 Oil return control on heating mode
■Oil return operation time : 3min for running step
■ Starting condition:same as cooling mode
■ Oil return process ends if compressor protection control starts
Outside Unit
Indoor Unit
OFF
Min. pulse
Normal control
Ending
ON
1200 pulse
1200 pulse
Running
OFF
Min. pulse
Normal control
Starting
Hot gas bypass valve
4way valve
Main EEV
Inv Compressor
Component
Normal control
OFF
Max. pulse
25Hz
Starting
Normal control
OFF
Max. pulse
Setting Value
Running
Normal control
ON
Max. pulse
25Hz
Ending
Oil return signal
Thermo off unit EEV
Thermo on unit EEV
Component
Function

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Copyright ©2013 LG Electronics. Inc. All right reserved.
Only for training and service purposes LGE Internal Use Only
2.2 Stopping operation
2.2.1 Stopping operation on cooling mode
After 15min.
(Before 15min. : ON)
-
After 15min.
(Before 15min. : Min. pulse)
-
Note
OFF
OFF
Max. pulse
0Hz
Operation
Hot gas bypass valve
4way valve
Main EEV
Inv Compressor
Component
After 15min.
(Before 15min. : ON)
After 60min.
After 15min.
(Before 15min. : Min. pulse)
-
Note
OFF
OFF
Max. pulse
0Hz
Operation
Hot gas bypass valve
4way valve
Main EEV
Inv Compressor
Component
Function
2.2.2 Stopping operation on heating mode