Power Supply Insufficient Or Instantaneous Abnormality - Daikin VRV X RXQ6-48ANR Series Service Manual

SiME341909EA

5.51 Power Supply Insufficient or Instantaneous Abnormality

Applicable All outdoor unit models
Models
U2
Error Code
Method of Error Detect the voltage of capacitor of the main circuit in the inverter PCB.
Detection
Error Decision
When the voltage in the DC circuit (between diode module and power module) falls below
Conditions 380 VDC.
Supposed
 Abnormal power supply voltage
Causes  Instantaneous power failure
 Open phase
 Defective inverter PCB
 Defective outdoor unit main PCB
 Defective compressor
 Defective main circuit wiring
 Defective fan motor
 Defective connection of signal cable
Troubleshooting
Part 6 Service Diagnosis
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
Check in Monitor Mode
For the models equipped with 2
compressors, check the
compressor M1C or M2C
applicable to the error code U2
while in monitor mode of the
outdoor unit.
Check for power supply
conditions.
(1) Power supply voltage falls
within the range of 380 to
415 V?
(2) Any open phase in the
power supply wiring or
any wrong wiring?
(3) Imbalance in the power
supply voltage is
maintained within 12 V?
There are some
defects in the power
supply conditions
aforementioned.
NO
The insulation
resistance of the
compressor is not more
than 100 kΩ.
NO
A
Go to the next page
YES
YES
Troubleshooting by Error Code
Remedy the defects.
Replace the compressor.
RXQ6-12AR: M1C
RXQ14/16AR: M1C, M2C
237