Refrigerant Shortage - Daikin VRV RXYQ72-384XAYCA Service Manual

SiUS342004EB

3.58 Refrigerant Shortage

Applicable
All outdoor unit models
Models
U0
Error Code
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.
Conditions  Error is not determined. The unit continues the operation.
Supposed
 Refrigerant shortage or refrigerant clogging (wrong piping)
Causes  Defective thermistor
 Defective low pressure sensor
 Defective outdoor unit main PCB
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
Reference
CHECK 2 Refer to page 358.
Reference
CHECK 12 Refer to page 369.
Part 6 Service Diagnosis
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
pressure 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 12)
Is the
characteristics of
NO
low pressure sensor
normal? (∗2)
YES
Troubleshooting by Error Code
NO
Replace the low pressure
sensor (S1NPL).
Replace the outdoor unit
main PCB (A1P).
Eliminate factors that cause
decreasing low pressure.
CHECK 2
324