Daikin VRV IV Q+ Series Installer And User Reference Manual page 148

24 | Troubleshooting
Main code
Master
Installer and user reference guide
148
Sub code
Slave 1 Slave 2
Cause
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)
Solution
▪ 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.
RXYQQ8~20U7Y1B
VRV IV Q+ series heat pump
4P546229-1A – 2020.10