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_TROUBLE SHOOTING GUIDE BOOK _
1. The Phenomena from Main Component Failure
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Copyright ©2017 LG Electronics. Inc. All right reserved.
Only for training and service purposes
LGE Internal Use Only
1. The phenomena from main component failure
The phenomena from main component failure
When system fault occurs, the error code is displayed on the indoor unit display or remote control display. The
trouble shooting guide is available in the service manual.
• When CH05/53/11 ERROR occurs, check if auto-addressing has done and communication wiring is ok.
Compressor
Outdoor
fan
Outdoor
EEV
Not operating
Stop during running
Abnormal noise
during running
High pressure error
in cooling mode
operation
Heating failure, fre-
quent defrosting
No operation sound
after switching ON
the power supply
Heating failure,
frozen outdoor heat
exchanger part
Low pressure error
or discharge temper-
ature error
Motor insulation broken
Strainer clogged
Oil leakage
Motor insulation failure
R-S-T misconnection
Motor failure,
bad ventilation around
outdoor heat exchanger
Bad connector contact
Coil failure
EEV clogged
EEV clogged
Check resistance between terminals and
chassis
Change strainer
Check Oil level after opening oil port
Check resistance between terminals and
chassis
Check compressor R-S-T connection
Check the fan operation to confirm proper
motor functioning. Switch OFF the outdoor
unit and remove obstacles, if any, around
the HEX. Check connector
Check resistance between terminals
Service necessary
Service necessary
Component Phenomenon Cause Check method and Trouble shooting
The phenomena from main component failure
2.1 Failure Judge Method
2.2 Failure Cause
2. Compressor
1. Error display (CH21, CH22, CH26, CH29)
- Failure to restart after power reset
- Main power supply failure from inverter board to compressor
- Compressor input current is normal but compressor fails to start
with electric noise from inverter board
- CH29 in normal operation and cycle
2. Phase current , input current hunting
- The phase current, input current value is hunting more than 5A in
stable state of high / low pressure and compressor Hz
3. Coil resistance (U-V, V-W, W-U) and insulation resistance measurement
- Insulation resistance : 50MΩ or more
- Coil resistance : refer to below
· Failure to obtain discharge superheat (refrigerant overcharging)
· High discharge temperature (refrigerant shortage)
· Failure to obtain high and low pressure difference
· Defective compressor
· Foreign substance inflow
· Overload operation
· Nitrogen / Vapor inflow and poor vacuum
· Defective oil return valve
· Oil return piping blocked
· Defective VI EEV
· Defective oil balancing valve
· Oil shortage due to oil leakage
· Lack of oil due to frequent Thermo On / Off
LGE Internal Use Only
1-2. 압축기 불량 판단
CH21, CH22, CH26, CH29
• 전원 Reset 후 재기동 여부 확인
• 압축기에 Inv보드에서 전원 인가 확인.
• 압축기 기동시 인버터 보드에서 전자기음과 함께 압축기에 투입되는 전류가 상승함에도 압축기 기동 안함.(CH26)
• 정상 운전 중 cycle의 특이한 변화가 없는데도 CH29 발생
상전류/입력전류 헌팅
• 고/저압 및 압축기 Hz가 고정되어 있으나 상전류 or 입력전류 값이 ±5 A 이상으로 헌팅할 경우 압축기 손상 판단됨.
압축기 상간 저항 및 절연 저항 측정
JQC068MA
*
Temp. 25 ℃ 75 ℃
U-V 0.216 ± 7 % Ω 0.258 ± 7 % Ω
V-W 0.216 ± 7 % Ω 0.258 ± 7 % Ω
W-U 0.216 ± 7 % Ω 0.258 ± 7 % Ω
JQC048MA
*
Temp. 25 ℃ 75 ℃
U-V 0.302 ± 7 % Ω 0.360 ± 7 % Ω
V-W 0.302 ± 7 % Ω 0.360 ± 7 % Ω
W-U 0.302 ± 7 % Ω 0.360 ± 7 % Ω
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