Panasonic U-8MF2E8 Service Manual page 141

4. 3WAY Alarm Codes
H08, H27 Alarm
Alarm code H08, H27
Alarm meaning Trouble (open circuit) with the oil sensor (connection) at compressor 1 and compressor 2
Alarm conditions This alarm occurs when a connector connection (pins 1 and 2 for compressor 1, pins 4
and 5 for compressor 2) is open.
Probable cause Disconnected connector
Check Check that the connector is securely connected.
Correction (1) Connect the connector.
(2) Correct the connection at connector pins 4 and 5.
Example —
Notes
H31 Alarm
Alarm code H31
Alarm meaning HIC trouble alarm
Alarm conditions This alarm occurs when the microcomputer identifies a trouble signal (indicating abnormal HIC
temperature or other trouble) from the HIC.
The HIC judges the current and temperature, and outputs the trouble signal. In general this
indicates trouble with the HIC itself.
Probable cause Overcurrent in HIC circuit, and the resultant abnormal heating, caused by HIC failure
Check Check the power wiring and connector wiring. If the wiring and connectors are normal, use a
tester to measure the resistance between the compressor HIC power (HIC+) and ground (HIC–).
If there is a short-circuit, there is an HIC malfunction.
HIC PCB for 8HP to 16HP
(A747038)
Correction If an HIC failure is found, replace the PCB.
Example —
Notes Turn OFF the power, and check the continuity of HIC+ and HIC– on the HIC PCB.
L04 Alarm
Alarm code L04
Alarm meaning Outdoor system address duplication
Alarm conditions Communication by inter-unit control wiring was received that contained the same address as that
unit 5 times or more within 3 minutes.
Probable cause Incorrect outdoor system address settings
Check Check the system address settings again.
Correction Correct the system address settings.
Example —
Notes Recovery from this alarm occurs automatically (when communication that contains the same
address as that unit is not received for 3 minutes after detection).
HIC -
(NV)
HIC +
(P)
5 - 19
3WAY SYSTEM
Trouble Diagnosis
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