Panasonic U-4LE2E5 Service Manual & Test Run Service Manual page 144

3. Mini VRF Alarm Codes
L04 Alarm
Alarm code
Alarm meaning
Alarm conditions
Probable cause
Check
Correction
Example
Notes
L10 Alarm
Alarm code
Alarm meaning
Alarm conditions
Probable cause
Check
Correction
Example
Notes
L18 Alarm
Alarm code
Alarm meaning
Alarm conditions
Probable cause
Check
Correction
Example
Notes
6
L04
Duplicate system address setting on outdoor units.
Communication by inter-unit control wiring was received that contained the same address as
that unit 5 times or more within 3 minutes.
Incorrect outdoor system address settings
Check the system address settings again.
Correct the system address settings.
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Recovery from this alarm occurs automatically (when communication that contains the same
address as that unit is not received for 3 minutes after detection).
L10
Capacity setting of outdoor unit is not correct.
The outdoor unit capacity has not been set, or the setting is not allowed by the system.
This alarm occurs because the capacity has not been set.
Connect the outdoor unit maintenance remote controller. On the outdoor unit EEPROM detailed
setting mode screen, check the value for the outdoor unit capacity (item code 81).
Check that it is not set to "0" or to a capacity that is not allowed.
If item code 81 is incorrect, use the outdoor unit maintenance remote controller and set it
correctly.
* After changing the setting, be sure to reset both the indoor and outdoor power.
—
The outdoor unit maintenance remote controller is required in order to set the capacity in the
outdoor unit EEPROM.
L18
4-way valve has failure.
During heating operation, the detected temperature at an outdoor unit heat exchanger (EXL) was
20°C or more above the outdoor air temperature (TO) continuously for 15 minutes or longer, or
the detected suction temperature (SCT) was 20°C or more above the outdoor air temperature
continuously for 5 minutes or longer.
(1) The 4-way valve connector (20S) has become disconnected from the Outdoor Unit Control
PCB.
(2) The 4-way valve circuit is locked (malfunctioning).
(1) Check the 4-way valve connector (20S).
(2) If the connector is normal, check the 4-way valve wiring and the Outdoor Unit Control PCB
circuit.
If the connector is normal, correct or replace the problem locations.
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Mini VRF SYSTEM
Trouble Diagnosis