LG A2UW18GFA0, Svc Manual

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Only for training and service purposes
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Part 5. Trouble Shooting
Display
code
Title Cause of error Check point & Normal condition
27
Over-current on AC
→
DC
converter circuit
• Overload operation
(Outdoor fan constraint,
screened, blocked)
• Wrong application of
Reactor Spec.
• Burned PCB internal
parts (PSC Module)
• Check outdoor fan constraint/ screened/ flow
structure
• Check Reactor Spec: 11A/ 13mH
• Check for PCB internal part burn
• Inspecting PCB IGBT part
1. Remove the connectors to the PCB.
2. Set Multi-tester as Resistance
measurement mode
3. Measure Resistance of Gate-collector,
Emitter-collector.
4. If the measurements are 1MΩ
↓ ,
the parts are decided as burned.
Is the unit properly
installed?
• Check fan locking
• Remove blockings around heat exchanger
• Maintain distance between outdoor unit
and the wall
• Check pipe folding and abnormality
• Check service valve lock
• Remedy : remove cause of error
• Remedy : replace reactor.
• Remedy : replace PCB Assembly.
• Check Reactor spec:1 1A/13mH
• Check IGBT part
resistance measurements
at power-on standby state
→ 100Ω ↑
Is the reactor
normal?
Is IGBT Part
is normal?
IGBT
Recheck power and
installation condition
Yes
WARNING
Before checking PCB or each outdoor electric parts, wait for 3 minutes after the power is off. When measuring at standby state
of power supply, after checking the measurement mode of the meter, be careful of the short-circuits with other parts.