Daikin VRV IV RXMLQ8T7Y1B Series - Error Codes: Overview

9 Troubleshooting
Installation and operation manual
26
RXMLQ8 + RXYLQ10~14T7Y1B*
VRV IV system air conditioner
4P543426-1 – 2018.07
9.2 Error codes: Overview
Main code Sub code Cause Solution
Master Slave 1 Slave 2
High pressure switch was activated
(S1PH, S2PH) - A1P (X3A; X4A)
Check stop valve situation or
abnormalities in (field) piping or airflow
over air cooled coil.
▪ Refrigerant overcharge
▪ Stop valve closed
▪ Check refrigerant amount+recharge
unit.
▪ Open stop valves
Stop valve closed (liquid) Open liquid stop valve.
▪ Refrigerant overcharge
▪ Stop valve closed
▪ Check refrigerant amount+recharge
unit.
▪ Open stop valves.
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) (Y2E) - A1P (X21A)
Check connection on PCB or actuator.
Electronic expansion valve malfunction
(main) (Y1E) - A1P (X23A)
Check connection on PCB or actuator.
Electronic expansion valve malfunction
(storage vessel) (Y3E) - A1P (X22A)
Check connection on PCB or actuator
Discharge temperature too high
(R21T/R22T):
▪ Stop valve closed
▪ Refrigerant shortage
▪ Open stop valves.
▪ Check refrigerant amount+recharge
unit.
Compressor casing temperature too
high (R8T):
▪ Stop valve closed
▪ Refrigerant shortage
▪ 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 (R1T) - A1P (X18A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction (R21T): open circuit - A1P
(X29A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction (R21T): short circuit - A1P
(X29A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction (R22T): open circuit - A1P
(X29A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction (R22T): short circuit - A1P
(X29A)
Check connection on PCB or actuator.
Compressor casing temperature
sensor malfunction (R8T): open circuit
- A1P (X29A)
Check connection on PCB or actuator.
Compressor casing temperature
sensor malfunction (R8T): short circuit
- A1P (X29A)
Check connection on PCB or actuator.
Suction temperature sensor
malfunction (R3T) - A1P (X30A)
Check connection on PCB or actuator.
De-icing temperature sensor
malfunction (R7T) - A1P (X30A)
Check connection on PCB or actuator