Daikin VRV S RXQ4/5ARV1 Service Manual page 302

Troubleshooting by Error Code
5.55.3 Refrigerant Shortage (10/12 HP Models)
Applicable
RXMQ10/12AR
Models
U0
Error Code
Method of Error Refrigerant shortage check is conducted based on the discharge pipe thermistor temperature
Detection and the low-pressure saturated temperature.
Error Decision
Low pressure becomes 0.1 MPa or below.
Conditions
Supposed
 Refrigerant shortage or refrigerant clogging (piping error)
Causes  Defective thermistor
 Defective low pressure sensor
 Defective outdoor unit main PCB (A1P)
Troubleshooting
Note(s)
1. Check the low pressure value by using pressure gauge in operation.
2. Compare the actual measurement value by pressure sensor with the value by the pressure
gauge.
Reference
CHECK 2 Refer to page 338.
Reference
CHECK 12 Refer to page 353.
296
Be sure to turn off the power switch before connecting or disconnecting
Caution connectors, or parts may be damaged.
(1) Set up a pressure gauge at the service port on the low
pressure side.
(2) Reset the operation using the remote controller then restart.
Check if the low
pressure is 0.1 MPa or
below. ( 1)
YES
CHECK 12
NO
Check if the property of
low pressure sensor
is normal.
( 2)
YES
SiAF332111E
NO
Replace the low pressure
sensor.
Replace the outdoor unit main
PCB (A1P).
Eliminate factors that cause
decreasing low pressure by
referring to CHECK 2 .
Part 6 Service Diagnosis