Daikin VRV IV Series - Page 128

22 | Troubleshooting
Installer and user reference guide
128
RKXYQ5T8+8T7Y1B + RDXYQ5T8+8T7V1B
VRV IV heat pump for indoor installation
4P499898-1B – 2021.12
Main code Sub code Cause Solution
Low pressure malfunction:
▪ Stop valve closed
▪ Refrigerant shortage
▪ Indoor unit malfunction
▪ Open stop valves.
▪ Check refrigerant amount+recharge
unit.
▪ Check the user interface's display or
transmission wiring between the
outdoor unit and the indoor unit.
Electronic expansion valve malfunction
(subcool)
Compressor unit: (Y1E) - A1P (X21A)
Check connection on PCB or actuator.
Electronic expansion valve malfunction
(main)
Heat exchanger unit: (Y1E) - A1P (X7A)
Check connection on PCB or actuator.
Discharge temperature too high:
▪ Stop valve closed
▪ Refrigerant shortage
Compressor unit: (R21T) - A1P (X29A)
▪ Open stop valves.
▪ Check refrigerant amount+recharge
unit.
▪ Refrigerant overcharge
▪ Stop valve closed
▪ Check refrigerant amount+recharge
unit.
▪ Open stop valves.
Ambient temperature sensor
malfunction
Heat exchanger unit: (R1T) - A1P (X16A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction
Compressor unit: (R21T): open circuit -
A1P (X29A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction
Compressor unit: (R21T): short circuit -
A1P (X29A)
Check connection on PCB or actuator.
Heat exchanger gas sensor malfunction
Heat exchanger unit: (R2T) - A1P (X18A)
Check connection on PCB or actuator.
Suction temperature sensor
malfunction
Compressor unit: (R3T) - A1P (X30A)
Check connection on PCB or actuator.
Suction temperature sensor
malfunction
Compressor unit: (R7T) - A1P (X30A)
Check connection on PCB or actuator.
De-icing temperature sensor
malfunction
Heat exchanger unit: (R3T) - A1P (X17A)
Check connection on PCB or actuator