Panasonic CS-VZ9SKE Service Manual page 123

17.4.22 F11 (Cooling-Heating Switching Error)
Troubleshooting
F11 occurred during cooling operation: Perform cooling operation and check if the
F11 occurred during heating operation: Perform heating operation and check if the
The above symptom is
not observed
Check for bad connection of the connector of the indoor unit pipe
temperature sensor.
Check for the characteristics of the indoor unit pipe temperature sensor.
Refer to the characteristic table for electronic circuit diagram.
(Remove the connector and check the resistance value of the sensor.)
Check of the voltage applied to 4-way valve coil during operation.
(Latch-type)
Two times of DC12V on the cooling or heating side terminal of the 4-way valve
coil for about 2 seconds (Interval is 5 to 240 sec).
(DC-driven type)
The following voltage is present on the both ends of the 4-way valve coil:
Heating operation: DC15V for 4 sec at the start and subsequently DC3V
Cooling operation: DC0V
Refer to electronic circuit diagram for the driving method of 4-way valve.
Check for the continuity of the 4-way valve coil.
Diagnosis Procedures and Cause
pipe temperature goes down.
pipe temperature goes up.
The above symptom is observed
No abnormality is observed
No abnormality is observed
For some models, the sensor is not connected by a connector but
it is directly soldered to the board.
In this case, replace the control board.
No abnormality is observed
There is continuity
Disconnection/
Imperfect
connection of
the connector
An abnormality
is observed
An abnormality
is observed
There is no
continuity
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Measures to be Taken
Fix the problem.
Replace the indoor unit pipe
temperature sensor.
Replace the indoor unit control board.
Replace the outdoor unit control board.
Replace 4-way valve coil.
Replace 4-way valve.