Code
number
Category
Abnormality
Cause
20
Sensor on
outdoor unit
Abnormality of the compressor
thermistor
Incorrect Wiring, Disconnecting Wiring,Breaking Wire, Short Circuit
21
Abnormality of high pressure sensor
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 DIP switch 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
35
Incorrect indoor unit number setting
Duplication of indoor unit number in same refrigerant cycle number
36
Incorrect 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
Voltage or combination of outdoor unit
models incorrectly set
Voltage or combination of secondary and main units incorrectly set
3d
Abnormal transmission between the
main unit and the secondary unit(s)
Incorrect wiring, disconnected wiring, broken cable, PCB fault
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 (Compressor, Inverter damage)
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, 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
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
OTHER INDICATIONS
PMML0496 rev.1 - 12/2020
74