Refrigerant Shortage - Daikin Aurora Series Service Manual

Troubleshooting by Error Code

2.56 Refrigerant Shortage

U0
Error Code
Applicable
All outdoor unit models
Models
Method of Error
Detect refrigerant shortage according to a low pressure level or a difference in heat exchanging
Detection temperature from the suction pipe.
Error Decision Low pressure becomes 0.1 MPa (14.5 psi) or less.
∗ Error is not determined. The unit continues the operation.
Conditions
Supposed
Causes
Troubleshooting
∗1. Check the low pressure value by using pressure gauge in operation.
Notes:
∗2. Compare the actual measurement value by pressure sensor with the value by the pressure
CHECK 12
253
Refrigerant shortage and refrigerant clogging (wrong piping)
Defective thermistor
Defective low pressure sensor
Defective outdoor unit main PCB
Be sure to turn off the power switch before connecting or disconnecting
Caution
connectors, or parts may be damaged.
(1) Mount a pressure gauge at the service port on the low
pressure side.
(2) Reset the operation using the remote controller then
restart.
Is the low
pressure 0.1 MPa
(14.5 psi) or less?
(∗1)
YES
gauge.
(To gain actual measurement value by pressure sensor, measure the voltage at the connector
[between (2)-(3)] and then convert the value into pressure.
CHECK 2 Refer to page 284.
Refer to page 297.
Is the
characteristics of
NO
low pressure sensor
normal? (∗2)
YES
SiUS341802E
NO
Replace the low pressure
sensor (S1NPL).
Replace the outdoor unit
main PCB (A1P).
Remove the factor of
decreasing low pressure.
CHECK 2
)
CHECK 12
Service Diagnosis