No.
Fault code
Fault
Cause/Remedy
5
4
3
2
1
19
●
∘
∘
●
●
EEPROM of the com-
munication PCB
(MSMP) faulty
Replace communication
PCB
20
●
∘
●
∘
∘
Processor overtem-
perature cut-out
21
●
∘
●
∘
●
Defrosting
22
●
∘
●
●
∘
Compressor over-
heated
23
●
∘
●
●
●
Compressor overcur-
rent
...
(N/A)
27
●
●
∘
●
●
Poor transmission
quality
Check the connecting cable
between the internal device,
the external unit and earth
...
(N/A)
29
●
●
●
∘
●
No fault (heating
mode)
30
●
●
●
●
∘
No fault (cooling, de-
humidifying, ventila-
tion operation)
31
●
●
●
●
●
No fault (standby)
●
Cooling and heating LEDs illumi-
nate together
∘
Only the heating LED illuminates
Diagnosis at the external unit, type OT307H
The external unit is equipped with a programming unit with a three-digit display.
Menu structure overview on page 31.
Diagnosis
(cont.)
21
Troubleshooting
5692
689
GB