19 Troubleshooting
Installation and operation manual
41
REYQ8~20+REMQ5U7Y1B
VRV IV+ heat recovery
4P546222-1B – 2020.10
Main code
Sub code
Cause
Solution
Master
Slave 1
Slave 2
High pressure switch was activated
(S1PH, S2PH) – main PCB (X2A, X3A)
Check stop valve situation or
abnormalities in (field) piping or airflow
over air cooled coil.
▪ Refrigerant overcharge
▪ Stop valve closed
▪ Check refrigerant recharge
unit.
▪ Open stop valves
Stop valve closed (liquid)
Open liquid stop valve.
▪ Refrigerant overcharge
▪ Stop valve closed
▪ Check refrigerant recharge
unit.
▪ Open stop valves.
Low pressure malfunction:
▪ Stop valve closed
▪ Refrigerant shortage
▪ Indoor unit malfunction
▪ Open stop valves.
▪ Check refrigerant recharge
unit.
▪ Check the user interface's display or
transmission wiring between the
outdoor unit and the indoor unit.
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 recharge
unit.
Compressor casing temperature too
high (R15T) – main PCB (X19A):
▪ Stop valve closed
▪ Refrigerant shortage
▪ Open stop valves.
▪ Check refrigerant recharge
unit.
▪ Refrigerant overcharge
▪ Stop valve closed
▪ Check refrigerant recharge
unit.
▪ Open stop valves.
Ambient temperature sensor malfunction
(R1T) – main PCB (X18A)
Check connection on PCB or actuator.
Summary of Contents for REYQ8U7Y1B
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