Panasonic OCU-CR200VF5 Operating Instructions And Installation Instructions page 50

Failure Diagnosis
Failure Diagnosis of Inverter Unit
(2) When inverter abnormality (E6 * to E7 *) is generated
Possible cause is as follows. Check all of the following causes.
Cause
Overload condition
Abnormality of power voltage
Failure of the INV-EN-PCB
When an external cause such as momentary power failure or lightening, or short duration of overload
Caution
occurs, an error is generated by momentary overcurrent even without any component failure.
Method of Checking
(1) Check if the compressor motor current is high.
(2) Check if any overload condition occurred even in a
short duration of time.
Check if the supplied power voltage to the refrigeration unit is
in the range of 220 V ± 22 V / 230 V ± 23 V / 240 V ± 24 V.
When the supplied voltage to the refrigeration unit is in the
range of 220V ± 22 V / 230V ± 23 V / 240 V ± 24 V, check
if any abnormality exists in the appearance or component
chipping of the INV-EN-PCB.
(1) Check if any difference exists between the motor
current of the compressor and the current value
displayed on the CRD1-EN-PCB.
(2) No problem if the difference in current value is ±10 % .
EN - 50
Method of Action
Eliminate the cause of overload.
Execute maintenance of the
power supply facility.
Replace the INV-EN-PCB.
Replace the INV-EN-PCB.