Panasonic U-4LE1E5 Service Manual page 103

3. Mini VRF System Alarm Codes
E20 No Indoor Units Error
1. Error Detection Method
It is judged an error if an indoor unit cannot be recognized at the start of auto address setting or when the outdoor unit is turned
on.
The address(es) of indoor unit(s) are not assigned correctly.
•
The indoor unit is not turned on.
•
2. Error Diagnosis
1 Indoor Unit
1-1 Are the address(es) of indoor unit(s) assigned correctly?
1-2 Are the indoor units turned on?
The indoor/outdoor control line may be disconnected somewhere between the indoor unit(s)
1-3
and the outdoor unit. Check and make sure the indoor/outdoor control line is connected.
5 - 23
Mini VRF SYSTEM
Trouble Diagnosis
Yes 1-2
No Set its address
Yes 1-3
No
Power on
5