Refrigerant Shortage - Daikin FTX50GV1B Service Manual

SiBE041029EB
4.6

Refrigerant Shortage

U0
Error Code
Method of Error Refrigerant shortage detection I:
Refrigerant shortage is detected by checking the input current value and the compressor
Detection
running frequency. If the refrigerant is short, the input current is lower than the normal value.
Refrigerant shortage detection II:
Refrigerant shortage is detected by checking the discharge pipe temperature and the opening of
the electronic expansion valve. If the refrigerant is short, the discharge pipe temperature tends
to rise.
Error Decision Refrigerant shortage detection I:
The following conditions continue for 7 minutes.
Conditions
<RX50/60G2V1B, 71 class>
RX50/60G2V1B
71 class
<RX50/60G3V1B>
RX50/60G3V1B
Refrigerant shortage detection II:
The following conditions continue for 80 seconds.
RX50/60G2V1B
RX50/60G3V1B
71 class
Supposed
Causes
Service Diagnosis
≤
Input current A × output frequency + B
Output frequency > C
A
(–)
18/1000
27/1000
Input current × input voltage
Output frequency > F
D
(–)
2000/256
Opening of the electronic expansion valve ≥ G
Discharge pipe temperature > H × target discharge pipe temperature + J
G (pulse)
480
480
450
If the error repeats, the system is shut down.
Reset condition: Continuous run for about 60 minutes without any other error
Disconnection of the discharge pipe thermistor, indoor or outdoor heat exchanger thermistor,
room or outdoor temperature thermistor
Closed stop valve
Refrigerant shortage (refrigerant leakage)
Poor compression performance of compressor
Defective electronic expansion valve
B C
(A)
0.7
2.0
≤
D × output frequency + E
E (W) F (Hz)
–181
H (–)
255/256 cooling: 20, heating: 45
128/128 cooling: 60, heating: 45
255/256
Troubleshooting
(Hz)
55
40
55
J (°C)
60
60