19 Troubleshooting
Installation and operation manual
40
RK RKXYQ8T7Y1B
VRV IV compressor unit for indoor installation
4P499900-1A – 2020.10
Main code
Cause
Solution
▪ No power is supplied to the compressor unit.
▪ Transmission wiring malfunction
▪ Check if all units are powered on.
▪ Check the transmission wiring.
▪ System mismatch. Wrong type of indoor units combined
(R410A, R407C, RA, etc). Indoor unit malfunction
▪ Heat exchanger unit malfunction
▪ Check if other indoor units have malfunction and confirm
indoor unit mix is allowed.
▪ Check the transmission wiring to the heat exchanger unit.
▪ Improper type of indoor units are connected.
▪ Mismatch of compressor unit and heat exchanger unit.
▪ Check the type of indoor units that are currently
connected. If they are not proper, replace them with
proper ones.
▪ Check if the compressor unit and heat exchanger unit are
compatible.
▪ The stop valves of the compressor unit are left closed.
▪ The piping and wiring of the specified indoor unit or heat
exchanger unit are not connected correctly to the
compressor unit.
▪ Open the stop valves on both the gas and liquid side.
▪ Confirm that the piping and wiring of the specified indoor
unit or heat exchanger unit are connected correctly to the
compressor unit.
In case of 8 HP:
Main code
Sub code
Cause
Solution
▪ Heat exchanger fan malfunction.
▪ Drain pump feedback contact is open.
In the heat exchanger unit:
▪ Check connection on PCB: A1P (X15A)
▪ Check connection on terminal block (X2M)
▪ Check the fan connectors.
Earth leakage detector activated
Compressor unit: (T1A) - A1P (X101A)
Restart the unit. If the problem reoccurs, contact
your dealer.
No earth leakage detector detected
Compressor unit: (T1A) - A1P (X101A)
Replace the earth leakage detector.
High pressure switch was activated
Compressor unit: (S1PH) - A1P (X4A)
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 (subcool)
Compressor unit: (Y1E) - A1P (X21A)
Check connection on PCB or actuator.
Electronic expansion valve malfunction (main)
Heat exchanger unit: (Y1E) - A1P (X7A)
Check connection on PCB or actuator.
Discharge temperature too high:
▪ Stop valve closed
▪ Refrigerant shortage
Compressor unit: (R21T) - A1P (X29A)
▪ Open stop valves.
▪ Check refrigerant recharge unit.
▪ Refrigerant overcharge
▪ Stop valve closed
▪ Check refrigerant recharge unit.
▪ Open stop valves.
Ambient temperature sensor malfunction
Heat exchanger unit: (R1T) - A1P (X16A)
Check connection on PCB or actuator.
Discharge temperature sensor malfunction
Compressor unit: (R21T): open circuit - A1P
(X29A)
Check connection on PCB or actuator.
Discharge temperature sensor malfunction
Compressor unit: (R21T): short circuit - A1P
(X29A)
Check connection on PCB or actuator.
