Daikin VRV RXYQ72-384XAYCA, Service Manual

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SiUS342004EB Troubleshooting by Error Code
Part 6 Service Diagnosis 324
Note(s)
Reference
Reference
3.58 Refrigerant Shortage
Applicable
Models
All outdoor unit models
Error Code
U0
Method of Error
Detection
Detect refrigerant shortage according to a low pressure level or a difference in heat exchanging
temperature from the suction pipe.
Error Decision
Conditions
Low pressure becomes 0.1 MPa (14.5 psi) or less.

Error is not determined. The unit continues the operation.
Supposed
Causes

Refrigerant shortage or refrigerant clogging (wrong piping)

Defective thermistor

Defective low pressure sensor

Defective outdoor unit main PCB
Troubleshooting
CHECK 2 Refer to page 358.
CHECK 12 Refer to page 369.
Is the low
press u re 0.1 MPa
(14.5 psi) or less?
(
∗
1)
Is the
characteristics of
low press u re sensor
normal? (
∗
2)
Replace the low press u re
sensor (S1NPL).
Replace the o u tdoor u nit
main PCB (A1P).
NO NO
YES YES
Eliminate factors that ca u se
decreasing low press u re.
CHECK 2
Caution
Be s u re to t u rn off the power switch b efore connecting or disconnecting
connectors, or parts may b e damaged.
(1) Mo u nt a press u re ga u ge at the ser v ice port on the low
press u re side.
(2) Reset the operation u sing the remote controller then
restart.
 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.
(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 )