Daikin VRV IV+ Installation And Operation Manual page 41

Main code
Master
RYYQ+RYMQ+RXYQ8~20U7Y1B
VRV IV+ heat pump
4P546220-1C – 2020.10
Sub code
Slave 1 Slave 2
Low pressure malfunction:
▪ Stop valve closed
▪ Refrigerant shortage
▪ Indoor unit malfunction
Electronic expansion valve malfunction
(main) (Y1E) - A1P (X21A)
Electronic expansion valve malfunction
(liquid cooling) (Y3E) - A1P (X23A)
Electronic expansion valve malfunction
(subcool) (Y2E) - A1P (X22A)
Electronic expansion valve malfunction
(storage vessel) (Y4E) - A1P (X25A)
Discharge temperature too high
(R21T/R22T):
▪ Stop valve closed
▪ Refrigerant shortage
Compressor casing temperature too
high (R8T/R9T):
▪ Stop valve closed
▪ Refrigerant shortage
▪ Refrigerant overcharge
▪ Stop valve closed
Ambient temperature sensor
malfunction (R1T) - A1P (X18A)
Discharge temperature sensor
malfunction (R21T): open circuit - A1P
(X19A)
Discharge temperature sensor
malfunction (R21T): short circuit - A1P
(X19A)
Discharge temperature sensor
malfunction (R22T): open circuit - A1P
(X19A)
Discharge temperature sensor
malfunction (R22T): short circuit - A1P
(X19A)
Compressor casing temperature
sensor malfunction (R8T): open circuit
- A1P (X19A)
Compressor casing temperature
sensor malfunction (R8T): short circuit
- A1P (X19A)
Compressor casing temperature
sensor malfunction (R9T): open circuit
- A1P (X19A)
Compressor casing temperature
sensor malfunction (R9T): short circuit
- A1P (X19A)
Suction temperature sensor
malfunction (R3T) - A1P (X30A)
De-icing temperature sensor
malfunction (R7T) - A1P (X30A)
Liquid temperature sensor (after
subcool HE) malfunction (R5T) - A1P
(X30A)
Liquid temperature sensor (coil)
malfunction (R4T) - A1P (X30A)
Cause
▪ 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.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator
Check connection on PCB or actuator
▪ Open stop valves.
▪ Check refrigerant amount+recharge
unit.
▪ Open stop valves.
▪ Check refrigerant amount+recharge
unit.
▪ Check refrigerant amount+recharge
unit.
▪ Open stop valves.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator.
Check connection on PCB or actuator
Check connection on PCB or actuator.
Check connection on PCB or actuator.
19 Troubleshooting
Solution
Installation and operation manual
41