Daikin VRV RXYQ72-384XAYCA, Service Manual

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Troubleshooting by Error Code SiUS342004EB
309 Part 6 Service Diagnosis
3.50 Inverter Radiation Fin Temperature Rise Abnormality
3.50.1 Inverter Radiation Fin Temperature Rise Abnormality (Inverter PCB)
Applicable
Models
All outdoor unit models
Error Code
L4
Sub code: 01-03
Method of Error
Detection
Detect temperature of power module of the inverter PCB.
Error Decision
Conditions
Thermistor located inside the power module of the inverter PCB for compressor and fan motor.
Cooling tube plate poor heat-exchange.
Supposed
Causes

Cooling tube plate not fixed with screws

U0 error

Defective inverter PCB

High outdoor air temperature

Incorrect power supply voltage

Defective connection of connectors
Troubleshooting
Continue operation.
Field factor. Power module temperature
may have risen due to high outdoor air
temperature.
Turn ON the
power supply, and then
press the ON button
continuously. Does
the error
recur?
Power
supply voltage
falls within ±10% of
the rated voltage?
Replace the inverter PCB (A4P).
Connect to power supply within ±10%
of the rated voltage.
NO
YES
Rectify troubles.
Normal?
Power
OFF
NO
NO
Check for the cooling
conditions of cooling tube
used to cool the inverter.
(1) Is the cooling tube plate
fixed with screws?
(2) Error code U0 is displayed
on the Error History
screen.
YES
YES
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.