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17.4.22 F11 (Cooling-Heating Switching Error)
Troubleshooting
Diagnosis Procedures and Cause
Measures to be Taken
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.
There is continuity
No abnormality is observed
No abnormality is observed
The above symptom is observed
An abnormality
is observed
There is no
continuity
F11 occurred during cooling operation: Perform cooling operation and check if the
pipe temperature goes down.
F11 occurred during heating operation: Perform heating operation and check if the
pipe temperature goes up.
Check for the continuity of the 4-way valve coil.
Replace the indoor unit control board.
Replace 4-way valve.
Replace the outdoor unit control board.
Replace 4-way valve coil.
Disconnection/
Imperfect
connection of
the connector
Check for bad connection of the connector of the indoor unit pipe
temperature sensor.
Fix the problem.
An abnormality
is observed
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.)
Replace the indoor unit pipe
temperature sensor.
The above symptom is
not observed
No abnormality is observed
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.
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