SiME332106E
Troubleshooting by Error Code
Part 6 Service Diagnosis
243
5.54 Refrigerant Shortage Abnormality (Heating Only)
Applicable
Models
All outdoor unit models
Error Code
U0
Sub code: -08
Method of Error
Detection
Detects refrigerant shortage according to the difference between low pressure equivalent
saturation temperature and suction pipe temperature, opening degree of main electronic
expansion valve or indoor unit electronic expansion valve, inverter fin temperature, or outdoor
air temperature, etc.
Error Decision
Conditions
All of the following conditions are satisfied for 5 minutes or more, 4 times within 240 minutes.
Suction pipe temperature – Low pressure equivalent saturation temperature > 15°C
Opening degree of main electronic expansion valve (Y1E) > 480 pulses
Inverter fin temperature < Outdoor air temperature
Outdoor air temperature – Low pressure equivalent saturation temperature > 15°C
Opening degree of the electronic expansion valve of all the indoor units that have thermostat
ON is 400 pulses or more
High pressure equivalent saturation temperature – Thermostat ON indoor unit liquid pipe
temperature < 5°C
Compressor operates in minimum step
Supposed
Causes
Refrigerant shortage and refrigerant clogging (wrong piping)
Defective thermistor
Defective inverter fin temperature thermistor
Defective inverter PCB (RXYMQ4-6AYFK)
Defective low pressure sensor
Defective electronic expansion valve coil (Y3E)
Defective outdoor unit main PCB
Troubleshooting
Replace the outdoor air
thermistor (R1T).
YES
YES
Are the
characteristics of the
outdoor air thermistor
(R1T) normal?
NO
Are the
characteristics of the
suction pipe
thermistor (R3T)
normal?
Replace the suction pipe
thermistor (R3T).
NO
Caution
Be sure to turn off the power switch before connecting or disconnecting
connectors, or parts may be damaged.
A
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CHECK 11
CHECK 11
