Service manual

Troubleshooting SiBE06-708_C
88 Service Diagnosis
4.6 Refrigerant Shortage
Error Code
U0
Method of Error
Detection
Refrigerant shortage detection I:
Refrigerant shortage is detected by checking the input current value and the compressor
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.
Refrigerant shortage detection III:
Refrigerant shortage is detected by checking the difference between suction and discharge
temperature.
Error Decision
Conditions
Refrigerant shortage detection I:
The following conditions continue for 7 minutes.
<25/35 class, RXS50K2V1B>

Input current × input voltage
≤
A × output frequency + B

Output frequency > C
<RK(X)S50F2V1B, RK(X)S50G2V1B, RXS50J2V1B>

Input current
≤
D × output frequency + E

Output frequency > F
Refrigerant shortage detection II:
The following conditions continue for 80 seconds.

Opening of the electronic expansion valve ≥ G

Discharge pipe temperature > H × target discharge pipe temperature + J
A
(–)
B (W) C (Hz)
25/35 class 640/256 0 55
RXS50K2V1B 2000/256 –181 55
D
(–)
E
(A)
F
(Hz)
RK(X)S50F2V1B
RK(X)S50G2V1B
RXS50J2V1B
18/1000 0.7 55
G (pulse) H (–) J (°C)
RK(X)S25/35F2V1B 480 255/256 30
RK(X)S25/35G2V1B
RK(X)S25/35G2V1B9
RXS25/35J2V1B
RXS25/35K2V1B
RXS25K3V1B
480 128/128 30
RK(X)S50F2V1B
RK(X)S50G2V1B
RXS50J2V1B
480 128/128 cooling: 20, heating: 45
RXS50K2V1B 480 128/128 cooling: 60, heating: 45