Panasonic CS-E12RB4UW Service Manual page 78

15.4.18 F91 (Refrigeration Cycle Abnormality)
Malfunction Decision Conditions

The input current is low while the compressor is running at higher than the setting frequency.
Malfunction Caused

Lack of gas.

3-way valve close.
Troubleshooting
When F91 indication happens.
Check 3 way valve.
3-way valve opened?
Check for gas leaking source (Refer to H16).
Gas leaking?
Check other parts in refrigeration cycles.
YES
NO, gas amount is OK
78
For safety reason and to prevent
component breakdown, always switch
Caution
off the power before remove and
connect the component.
NO, closed
Open 3 way valve.
Check for gas leaking source;
YES
Repair or replace defected part(s).
Re-claim and then re-charge the right
amount.