Panasonic CS-Z20TKR Service Manual page 139

17.4.21 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 H16).
Gas leaking?
Check other parts in refrigeration cycles.
YES
NO, gas amount is OK.
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.
139
For safety reason and to prevent
component breakdown, always switch
off the power before remove and
connect the component.