Refrigerant Shortage Abnormality (Heating Only) - Daikin VRV RXYMQ-A Series Service Manual

SiME332106E

5.54 Refrigerant Shortage Abnormality (Heating Only)

Applicable All outdoor unit models
Models
U0
Error Code
Sub code: -08
Method of Error
Detects refrigerant shortage according to the difference between low pressure equivalent
Detection 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 All of the following conditions are satisfied for 5 minutes or more, 4 times within 240 minutes.
Conditions  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
 High pressure equivalent saturation temperature – Thermostat ON indoor unit liquid pipe
 Compressor operates in minimum step
Supposed
 Refrigerant shortage and refrigerant clogging (wrong piping)
Causes  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
Part 6 Service Diagnosis
ON is 400 pulses or more
temperature < 5°C
Be sure to turn off the power switch before connecting or disconnecting
Caution
connectors, or parts may be damaged.
CHECK 11
Are the
characteristics of the
outdoor air thermistor
(R1T) normal?
YES
CHECK 11
Are the
characteristics of the
suction pipe
thermistor (R3T)
normal?
YES
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A
NO
NO
Troubleshooting by Error Code
Replace the outdoor air
thermistor (R1T).
Replace the suction pipe
thermistor (R3T).
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