Daikin REYQ12T7Y1B - Page 29

8 Troubleshooting
Installation and operation manual
29
REYQ8~20+REMQ5T7Y1B
VRV IV system air conditioner
4P353996-1E – 2018.04
Main code Sub code Cause Solution
Master Slave 1 Slave 2
Electronic expansion valve malfunction
(upper heat exchanger) (Y1E) – main
PCB (X21A)
Check connection on PCB or actuator.
Electronic expansion valve malfunction
(lower heat exchanger) (Y3E) – main
PCB (X23A)
Check connection on PCB or actuator.
Electronic expansion valve malfunction
(subcool heat exchanger) (Y2E) –
main PCB (X22A)
Check connection on PCB or actuator
Electronic expansion valve malfunction
(receiver gas) (Y4E) – main PCB
(X25A)
Check connection on PCB or actuator.
Electronic expansion valve malfunction
(inverter cooling) (Y5E) – sub PCB
(X8A)
Check connection on PCB or actuator.
Electronic expansion valve malfunction
(auto charge) (Y6E) - sub PCB (X10A)
Check connection on PCB or actuator.
Discharge temperature too high
(R21T/R22T) – main PCB (X19A):
▪ Stop valve closed
▪ Refrigerant shortage
▪ Open stop valves.
▪ Check refrigerant amount+recharge
unit.
Compressor casing temperature too
high (R15T) – main PCB (X19A):
▪ 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) – main PCB (X18A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction (R21T): open circuit –
main PCB (X19A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction (R21T): short circuit - main
PCB (X19A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction (R22T): open circuit - main
PCB (X19A)
Check connection on PCB or actuator.
Discharge temperature sensor
malfunction (R22T): short circuit - main
PCB (X19A)
Check connection on PCB or actuator.
Compressor casing temperature
sensor malfunction (R8T): open circuit
- main PCB (X19A)
Check connection on PCB or actuator.
Compressor casing temperature
sensor malfunction (R8T): short circuit
- main PCB (X19A)
Check connection on PCB or actuator.
Suction compressor temperature
sensor (R12T) – sub PCB (X15A)
Check connection on PCB or actuator.
Suction temperature sensor (R10T) –
main PCB (X29A)
Check connection on PCB or actuator.
Heat exchanger deicer temperature
sensor (R11T) – sub PCB (X15A)
Check connection on PCB or actuator
Upper heat exchanger – gas -
temperature sensor (R8T) – main PCB
(X29A)
Check connection on PCB or actuator.
Lower heat exchanger – gas -
temperature sensor (R9T) main PCB
(X29A)
Check connection on PCB or actuator.