Panasonic U-72MF1U9 Service Manual page 81

3. W-3WAY VRF Alarm Codes
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 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.
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 unit refrigerant 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).
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HIC
HIC PCB
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Trouble Diagnosis
HIC +
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