Panasonic U-4LE2E5 Service Manual & Test Run Service Manual page 143

3. Mini VRF Alarm Codes
H31 Alarm (U-4LE2E8, U-5LE2E8, U-6LE2E8)
Alarm code H31
Alarm meaning Compressor HIC has failure. HIC is overcurrent or overheat. VDC is undervoltage or overvoltage.
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 (1) Power supply voltage malfunction
(2) Overcurrent HIC caused the HIC failure by abnormal temperature.
Check (1) Check the power supply and voltage. Check whether the voltage between each of the phases
（It is necessary to check the compressor while running because the voltage may decrease
(2) Right or wrong decision of HIC PCB IPM
■ Right or wrong decision of HIC PCB IPM
(3) Radiation failure of HIC. Check the follows.
・ Confirm that radiation surface of the rear HIC PCB and the radiation plate of the electrical
・ No screws loose.
・ Cooling air flows properly through the rear radiation plate of the electrical component box
Correction (1) Correct the power supply voltage.
(2) HIC failure and PCB replacement
(3) Improve the HIC radiation failure. Additional description is required in the manual.
Example —
Notes Disconnect the power supply.
is correct while the compressor is running.
when the compressor starts running.）
Carry out the judgement of HIC PCB IPM in the following method. If the result of
measurement shows the resistance value of the fault diagnosis, replace the HIC PCB.
Measure the resistance value between the + side (P) and - side (NW) of the HIC PCB.
・ Use the analogue tester when measuring. Measure by the kΩ-range.
・ Measure as single item PCB. (Remove the wires, etc.)
・ Measure as terminal part. (See the figure.)
Resistance value of fault diagnosis: Less than 1kΩ
component box contact properly. Putty of thermal conductivity is proplery adhered.
(fin part). (Clogged in the airflow, etc.)
HIC PCB
HIC-
(NW)
6 - 15
Mini VRF SYSTEM
Trouble Diagnosis
HIC+
(P)
6