TROUBLESHOOTING
2.1.2 Alarms for Outdoor units
Alarm
Category
Code
Activation of protection device
2
Outdoor unit
(high pressure cut)
Abnormal transmission between outdoor and
3
indoor units
Transmission
Abnormal transmission between inverter PCB
4
and RASC unit PCB
Reception of abnormal operation code for
5
Power supply
detection of power source phase
Excessively low voltage or excessively high
6
Voltage
voltage for the inverter
7
Decrease in discharge gas superheat
Cycle
Excessively high discharge gas temperature at
8
the top of compressor
Activation of the protection device for the indoor
19
Fan motor
fan motor
Thermistor for discharge gas temperature
20
(THM9)
21
High pressure sensor
Outdoor unit
Thermistor for outdoor ambient temperature
sensor
22
(THM7)
24
Thermistor for evaporating temperature (THM8)
Incorrect capacity setting or combined capacity
31
between outdoor and indoor units
35
Incorrect indoor unit number setting
System
36
Incorrect of Indoor Unit Combination.
Abnormality of picking up circuit for protection
38
(Outdoor unit)
Activation of the safety device from excessively
45
high discharge pressure
Activation of the safety device from excessively
Protection
47
low suction pressure (protection from vacuum
device
operation)
48
Activation of overcurrent protection
51
Abnormal operation of the current sensor
Inverter fin temperature increase
53
Inverter
Abnormality of inverter fin temperature
54
55
Abnormality of inverter module
57
Outdoor
Activating the protection of the fan motor
5B
Outdoor fan
Activation of over current protection
51
PMML0626 rev.0 - 07/2022
Type of abnormality
Main cause
Activation of PSH, locked motor, abnormal operation in the power
supply phase.
Failure of fan motor, drain discharge, PCB, relay, float switch
activated.
(Pipe clogging, excessive refrigerant, innert gas mixing, fan motor
locking at cooling operation)
Incorrect wiring. Loose terminals, Failure of PCB. Tripping of fuse.
Power supply OFF.
Transmission failure between inverter PCBs. (Loose Connector,
Wire Breaking, Blowout of Fuse).
Power source with abnormal wave pattern. Main power supply
phase is reversely connected or one phase is not connected.
Voltage drop in power supply. Incorrect wiring or insufficient
capacity of power supply wiring.
Excessive Refrigerant Charge, Failure of Thermistor, Incorrect
Wiring, Incorrect Piping Connection, Expansion Valve Locking at
Opened Position (Disconnected Connector).
Insufficient refrigerant charge, refrigerant leakage. Expansion valve
closed or clogged.
Failure of fan motor.
Incorrect wiring, disconnected wiring, broken cable, short circuit.
Incorrect Wiring, Disconnected Wiring, Wire Breaking, Short
Circuit, Fan Motor Locking at Heating Operation.
Incorrect Capacity Code Setting, Excessive or Insufficient Indoor
Unit Total Capacity Code.
Duplication of indoor unit number, number of indoor units over
specifications.
Failure of indoor unit PCB, incorrect wiring, connection to PCB in
indoor unit.
Overload (obstruction of HEX, short circuit) mixture of inert gas,
Excessive Refrigerant.
Shortage or leakage of refrigerant, piping clogging, expansion
valve close-locked, fan motor locked.
Overload, overcurrent. Failure of Inverter PCB, heat exchanger
clogged, locked compressor. EVI/EVO failure.
Incorrect wiring of current sensor. Failure of control PCB or Inverter
PCB.
Inverter module (IPM, DIP-IPM) and Inverter PCB abnormality.
Failure of compressor, clogging of heat exchanger.
Heat Exchanger Clogging. Fan Motor Failure.
Failure of DIP-IPM, IPM or Inverter PCB.