8 Troubleshooting
Alarm codes displayed in the remote control switch
SMGB0137 rev.0 - 05/2021
284
Code
Category
Content of Abnormality
Leading Cause
20
Sensor on
Outdoor Unit
Abnormality of the compressor thermistor
21
Abnormality of high pressure sensor
Incorrect wiring, disconnecting wiring,
breaking wire, short circuit
22
Abnormality of outdoor air thermistor
23
Abnormality of discharge gas thermistor
on top of compressor
24
Abnormality of heat exchanger liquid pipe
thermistor
25
Abnormality of heat exchanger gas pipe
thermistor
29
Abnormality of low pressure sensor
30
System
Incorrect DSW settings of outdoor unit for
CH-Box
Connection of CH-Box to heat pump system, disconnection
of CH-Box to heat recover system.
31
Incorrect capacity setting of outdoor unit
and indoor unit
Incorrect capacity setting of outdoor unit and indoor unit,
excessive or insufficient indoor unit total capacity code
32
Incorrect setting of other indoor unit
number (RPK series only)
Problem with a different Indoor Unit in the same refrigerant
cycle; (Failure at the power supply, defective PCB)
35
Incorrect indoor unit number setting
Duplication of indoor unit number in same refrigerant cycle
number
36
Incorrect of indoor unit combination
Indoor unit is designed for R22
38
Abnormality of picking up circuit for
protection (outdoor unit)
Failure of protection detecting device (incorrect wiring of
outdoor PCB)
39
Compressor
Abnormal operation current in constant
speed compressor
Overcurrent, blown fuse, current sensor fault, instant power
failure, voltage drop, abnormal power supply
3A
Outdoor Unit
Abnormal outdoor unit capacity
Outdoor unit capacity > Permitted maximum
3b
Incorrect setting of outdoor unit models
combination or voltage
Incorrect setting of main and sub units(s) combination or
voltage
3d
Abnormal communication between main
unit and sub unit(s)
Incorrect wiring, disconnect wire, breaking wire, PCB failure
3E
Abnormal combination between inverter
PCB and outdoor PCB
Incorrect combination between inverter PCB and outdoor
PCB
41
Protection
Device
Cooling overload (possible activation of
high pressure device)
If the outdoor unit pipe thermistor temperature is higher than
55ºC and the compressor top temperature is higher than
95ºC, outdoor unit pretection device is activated.
42
Heating overload (possible activation of
high pressure device)
If the indoor unit freeze protection thermistor temperature
is higher than 55ºC and the compressor top temperature is
higher than 95ºC, outdoor unit pretection device is activated
43
Activation of the protection device from
compression ratio decrease
Abnormal compression (failure of compressor or inverter,
loose power supply connection)
44
Activation of the protection device from
excessively high suction pressure
Overload during cooling, high temperature with heating,
locked expansion valve
45
Activation of the protection device from
excessively high discharge pressure
Overload (obstruction of Heat exchanger or clogging, short
circuit) mixture of inert gas
47
Activation of the protection device
from excessively low suction pressure
(protection from vacuum operation)
Shortage or leakage of refrigerant, piping clogging,
expansion valve close-locked, fan motor locked
48
Abnormality of current sensor for inverter
Overload operation, compressor failure, failure of DIP-IPM,
heat exchanger clogged, locked compressor, EVI/EVO
failure or overcharge
51
Sensor
Abnormality of current sensor for inverter
Current sensor failure
53
Inverter
Protection activation of inverter module
Driver IC error signal detection (inverter module abnormality,
protection for overcurrent, voltage decrease, short circuit),
instantaneous overcurrent. Failure of compressor, clogging
of heat exchanger
54
Inverter fin temperature increase
Abnormal inverter fin thermistor, clogging of heat exchanger,
abnormal outdoor fan.
55
Inverter Module abnormality
Failure of inverter module (PCB failure)
56
Outdoor fan
Abnormal detection of fan motor position
Abnormal of fan motor position detection circuit,
disconnected wiring
