Daikin VRV IV+ RXYTQ8U5/U7YF Installation And Operation Manual

19 TroubleshootingInstallation and operation manual34RXYTQVRV IV+ heat pump for high ambient temperatures4P546223-1C – 2021.11Main code Sub code Cause SolutionMaster Slave 1 Slave 2Discharge temperature too high(R21T/R22T):▪ Stop valve closed▪ Refrigerant shortage▪ Open stop valves.▪ Check refrigerant amount+rechargeunit.Compressor casing temperature toohigh (R8T/R9T):▪ Stop valve closed▪ Refrigerant shortage▪ Open stop valves.▪ Check refrigerant amount+rechargeunit.▪ Refrigerant overcharge▪ Stop valve closed▪ Check refrigerant amount+rechargeunit.▪ Open stop valves.Ambient temperature sensormalfunction (R1T) - A1P (X18A)Check connection on PCB or actuator.Discharge temperature sensormalfunction (R21T): open circuit - A1P(X19A)Check connection on PCB or actuator.Discharge temperature sensormalfunction (R21T): short circuit - A1P(X19A)Check connection on PCB or actuator.Discharge temperature sensormalfunction (R22T): open circuit - A1P(X19A)Check connection on PCB or actuator.Discharge temperature sensormalfunction (R22T): short circuit - A1P(X19A)Check connection on PCB or actuator.Compressor casing temperaturesensor malfunction (R8T): open circuit- A1P (X19A)Check connection on PCB or actuator.Compressor casing temperaturesensor malfunction (R8T): short circuit- A1P (X19A)Check connection on PCB or actuator.Compressor casing temperaturesensor malfunction (R9T): open circuit- A1P (X19A)Check connection on PCB or actuator.Compressor casing temperaturesensor malfunction (R9T): short circuit- A1P (X19A)Check connection on PCB or actuator.Suction temperature sensormalfunction (R3T) - A1P (X30A)Check connection on PCB or actuator.De-icing temperature sensormalfunction (R7T) - A1P (X30A)Check connection on PCB or actuatorLiquid temperature sensor (aftersubcool HE) malfunction (R5T) - A1P(X30A)Check connection on PCB or actuator.Liquid temperature sensor (coil)malfunction (R4T) - A1P (X30A)Check connection on PCB or actuator.Gas temperature sensor (after subcoolHE) malfunction (R6T) - A1P (X30A)Check connection on PCB or actuator.High pressure sensor malfunction(S1NPH): open circuit - A1P (X32A)Check connection on PCB or actuator.High pressure sensor malfunction(S1NPH): short circuit - A1P (X32A)Check connection on PCB or actuator.Low pressure sensor malfunction(S1NPL): open circuit - A1P (X31A)Check connection on PCB or actuator.Low pressure sensor malfunction(S1NPL): short circuit - A1P (X31A)Check connection on PCB or actuator.