Model reference

LG LRNU18GS3B0

Air Conditioner

1 document151 error codes5 service modes

Available documentation

Service Manual

Air Conditioner Service Manual268 pg
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01 on my LG LRNU18GS3B0

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Indoor unit air temperature sensor is

From Service Manual 990026, p.38:

1.Access service mode to confirm the active fault code and read stored error history.

2.Disconnect the sensor and measure resistance. Expected: 10 kΩ to 12 kΩ at 77°F (25°C).

3.Check the sensor harness for opens. A reading outside 5 kΩ to 50 kΩ indicates a failed sensor.

Part 6322FR2046G

Temperature thermistor

Error codes (151)

CodeMeaning

01Indoor unit air temperature sensor is open or short.02Indoor unit inlet pipe temperature sensor is open or short.03Failing to receive wired remote controller signal at indoor unit PCB.04Malfunction of drain pump (float switch open due to rising condensate water…05Failing to receive outdoor unit signal at indoor unit PCB (indoor/outdoor…06Outlet pipe temperature sensor of indoor unit is open or short.07Operation mode between indoor unit and outdoor unit is different.09Indoor unit EEPROM error 10Indoor fan motor lock or disconnection 100System off due to excessive increase of discharge temperature of constant speed…101System off due to excessive increase of discharge temperature of constant speed…102System off due to excessive increase of discharge temperature of constant speed…103System off due to excessive increase of discharge temperature of constant speed…104Failing to receive sub1 signal at main PCB of main outdoor unit (transmission…105Failing to receive fan signal at main PCB (fan PCB to main PCB transmission…106Over-current of fan motor / IPM fault.107Low voltage of fan motor driver (DC voltage charging failure of inverter fan…108Failing to receive main signal at fan PCB (main PCB to fan PCB transmission…109High pressure switch of sub1 outdoor unit is operated by high pressure rising.11Indoor unit does not receive signal from outdoor unit for 3 minutes…110Reverse connection or omitting connection of R, S, T power of sub1 outdoor unit.111Failing to receive main signal at main PCB of sub1 outdoor unit (transmission…113Liquid pipe temperature sensor of main outdoor unit is open or short.114Subcooling inlet temperature sensor of main outdoor unit is open or short.115Subcooling outlet temperature sensor of main outdoor unit is open or short.116High pressure sensor of sub1 outdoor unit is open or short.117Low pressure sensor of sub1 outdoor unit is open or short.118Air temperature sensor of sub1 outdoor unit is open or short.120Suction temperature sensor of sub1 outdoor unit is open or short.121Discharge temperature sensor of constant speed compressor 1 of sub1 outdoor…

View all 151 error codes

122Discharge temperature sensor of constant speed compressor 2 of sub1 outdoor…123Temperature sensor of front-side heat exchanger of sub1 unit is open or short.124Temperature sensor of rear-side heat exchanger of sub1 unit is open or short.125Liquid pipe temperature sensor of sub1 outdoor unit is open or short.126Subcooling inlet temperature sensor of sub1 outdoor unit is open or short.127Subcooling outlet temperature sensor of sub1 outdoor unit is open or short.128High pressure sensor of sub2 outdoor unit is open or short.129Low pressure sensor of sub2 outdoor unit is open or short.130Air temperature sensor of sub2 outdoor unit is open or short.132Suction temperature sensor of sub2 outdoor unit is open or short.133Discharge temperature sensor of constant speed compressor 1 of sub2 outdoor…134Discharge temperature sensor of constant speed compressor 2 of sub2 outdoor…135Temperature sensor of front-side heat exchanger of sub2 unit is open or short.136Temperature sensor of rear-side heat exchanger of sub2 unit is open or short.137Liquid pipe temperature sensor of sub2 outdoor unit is open or short.138Subcooling inlet temperature sensor of sub2 outdoor unit is open or short.139Subcooling outlet temperature sensor of sub2 outdoor unit is open or short.140Compressor off due to the high pressure switch in sub2 outdoor unit.141Wrong wiring at sub2 outdoor unit (phase reversal / phase omission).142Transmission error between sub2 outdoor unit and main outdoor unit.143System off by excessive increase of high pressure of sub1 outdoor unit.144System off by excessive decrease of low pressure of sub1 outdoor unit.145System off by excessive increase of high pressure of sub2 outdoor unit.146System off by excessive decrease of low pressure of sub2 outdoor unit.147Input voltage of sub1 outdoor unit is more than 487V or less than 270V.148Voltage detection circuit of sub1 outdoor unit is out of order.149Input voltage of sub2 outdoor unit is more than 487V or less than 270V.150Voltage detection circuit of sub2 outdoor unit is out of order.151Failure of operation mode conversion 152System off due to excessive increase of discharge temperature of constant speed…153System off due to excessive increase of discharge temperature of constant speed…154High pressure switch of sub3 outdoor unit operated by high pressure rising.155Wrong wiring at sub3 outdoor unit (phase reversal / phase omission).156Transmission error 157High pressure sensor of sub3 outdoor unit is open or short.158Low pressure sensor of sub3 outdoor unit is open or short.159Air temperature sensor of sub3 outdoor unit is open or short.161Suction temperature sensor of sub3 outdoor unit is open or short.162Discharge temperature sensor of constant speed compressor 1 of sub3 outdoor…163Discharge temperature sensor of constant speed compressor 2 of sub3 outdoor…164Temperature sensor of front-side heat exchanger of sub3 unit is open or short.165Temperature sensor of rear-side heat exchanger of sub3 unit is open or short.166Liquid pipe temperature sensor of sub3 outdoor unit is open or short.167Subcooling inlet temperature sensor of sub3 outdoor unit is open or short.168Subcooling outlet temperature sensor of sub3 outdoor unit is open or short.169System off by excessive increase of high pressure of sub3 outdoor unit.170System off by excessive decrease of low pressure of sub3 outdoor unit.171Input voltage of sub3 outdoor unit is more than 487V or less than 270V.172Voltage detection circuit of sub3 outdoor unit is out of order.173Abnormal starting of main constant speed compressor 174Abnormal starting of sub1 constant speed compressor 1 175Abnormal starting of sub1 constant speed compressor 2 176Abnormal starting of sub2 constant speed compressor 1 177Abnormal starting of sub2 constant speed compressor 2 200Pipe detection error 201HR unit 1 liquid pipe temperature sensor is open or short.202HR unit 1 sub-cooling inlet pipe temperature sensor is open or short.203HR unit 1 sub-cooling discharge pipe temperature sensor is open or short.204Transmission error between HR unit 1 and outdoor unit.205HR unit 2 liquid pipe temperature sensor is open or short.206HR unit 2 sub-cooling inlet pipe temperature sensor is open or short.207HR unit 2 sub-cooling discharge pipe temperature sensor is open or short.208Transmission error between HR unit 2 and outdoor unit.209HR unit 3 liquid pipe temperature sensor is open or short.21IPM fault or overcurrent to inverter compressor.210HR unit 3 sub-cooling inlet pipe temperature sensor is open or short.211HR unit 3 sub-cooling discharge pipe temperature sensor is open or short.212Transmission error between HR unit 3 and outdoor unit.213HR unit 4 liquid pipe temperature sensor is open or short.214HR unit 4 sub-cooling inlet pipe temperature sensor is open or short.215HR unit 4 sub-cooling discharge pipe temperature sensor is open or short.216Transmission error between HR unit 4 and outdoor unit.217HR unit 5 liquid pipe temperature sensor is open or short.218HR unit 5 sub-cooling inlet pipe temperature sensor is open or short.219HR unit 5 sub-cooling discharge pipe temperature sensor is open or short.22Overcurrent flows to inverter compressor (CT current exceeds allowable maximum).220Transmission error between HR unit 5 and outdoor unit.221HR unit 6 liquid pipe temperature sensor is open or short.222HR unit 6 sub-cooling inlet pipe temperature sensor is open or short.223HR unit 6 sub-cooling discharge pipe temperature sensor is open or short.224Transmission error between HR unit 6 and outdoor unit.225HR unit 7 liquid pipe temperature sensor is open or short.226HR unit 7 sub-cooling inlet pipe temperature sensor is open or short.227HR unit 7 sub-cooling discharge pipe temperature sensor is open or short.228Transmission error between HR unit 7 and outdoor unit.229HR unit 8 liquid pipe temperature sensor is open or short.23DC voltage charging not performed after starting relay turn on for inverter…230HR unit 8 sub-cooling inlet pipe temperature sensor is open or short.231HR unit 8 sub-cooling discharge pipe temperature sensor is open or short.24System off by high pressure switch in main outdoor unit.240Central controller CNU connection failure 241Central controller data transmission error (CNU to central controller sending…242Central controller receive error 243Central controller receive buffer overflow 244Central controller to CNU data transmission failure 245Central controller send timeout 246Central controller receive timeout 25Input voltage is out of tolerable range (low/over voltage at main PCB).250Central controller check sum error 251Central controller receive zero error 252Central controller wrong address error 32System off due to rising of inverter compressor discharge temperature in main…33System off due to rising of constant speed compressor discharge temperature in…34System off by excessive increase of high pressure of main outdoor unit (3…35System off by excessive decrease of low pressure of main outdoor unit (3…40Current sensor (CT) of inverter compressor is open or short 41Discharge temperature sensor of inverter compressor is open or short.42Low pressure sensor of main outdoor unit is open or short.43High pressure sensor of main outdoor unit is open or short.44Air temperature sensor of main outdoor unit is open or short.45Temperature sensor of front-side heat exchanger is open or short.46Suction temperature sensor of main outdoor unit is open or short.47Discharge temperature sensor of the constant speed compressor of main outdoor…48Temperature sensor of rear-side heat exchanger is open or short.51Excessive connection of indoor units compared to capacity of outdoor unit (over…52Failing to receive inverter signal at main PCB (inverter PCB to main PCB…53Failing to receive indoor unit signal at main PCB of outdoor unit.54Reverse connection or omitting connection of R, S, T power of main outdoor unit.57Failing to receive main PCB signal at inverter PCB.62Overheat of inverter heatsink.65Temperature sensor of fan (heatsink) is open or short.

Service modes (5)

auto_addressing["Ensure all indoor and outdoor units are powered on.","Press address (red) button on Main PCB for…
data_display_mode["Turn on dip switch No.7 and No.8 on main PCB.","Press and hold the auto-addr push switch for 5…
forced_operation["Press the forced operation button (power button) on the indoor unit main body."]
instant_indoor_unit_checking["Set dip switch 1 on for cooling mode (or 1 and 2 on for heating mode).","Push address (red)…
test_operation["Press and hold ON/OFF button for 3-5 seconds until buzzer sounds 1 beep."]

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