Mitsubishi Electric PUHY-HP144TSHMU-A Service Handbook page 144

[ IX Troubleshooting ]
1. Error Code
4220
4225
Abnormal bus voltage drop (Detail code 108)
2. Error definition and error detection method
If Vdc 160V or less is detected during Inverter operation. (S/W detection)
3. Cause, check method and remedy
(1) Power supply environment
Check whether the unit makes an instantaneous stop when the detection result is abnormal or a power failure occurs.
Check whether the power voltage is 188V or less across all phases.
(2) Voltage drop detected
4220
Check the voltage between SCP1 and IPM N terminals on the INV board while the inverter is stopped and if it is 220 V or
above, check the following items.
1) Confirm on the LED monitor that the bus voltage is above 160 V. Replace the INV board if it is below 160 V.
2) Check the voltage at CN505 on the control board. ->Go to (3).
3) Check the coil connections (L1 - L3) and for coil burnout.
4) Check the resistance of the diode stack. ->Refer to [4]-6-(6).(page 203)
5) Check the wiring connections between the following sections
Between the noise filter board and INV board. Between the INV board and C1.
Replace the noise filter board if no problems are found.
Check the voltage between SCP1 and IPM N terminals on the INV board while the inverter is stopped and if it is less than 220
V, check the following items.
1) Check the connection to SCP1 and IPM N on the INV board.
2) Check the wiring between the noise filter board and INV board.
3) Check the resistance of the diode stack. ->Refer to [4]-6-(6).(page 203)
4) Check the in-rush current resistor value. ->Refer to [4]-6-(4).(page 201)
5) Replace the noise filter board.
4225
Check the voltage at CNVDC on the Fan board while the inverter is stopped and if it is 220 V or above, check the following
items.
1) Check the voltage at CN505 on the control board. ->Go to (3).
2) Check the coil connections (L1 - L3) and for coil burnout.
3) Check the wiring connections between the following sections
Replace the noise filter board if no problems are found.
If the problem recurs after replacing the noise filter, replace the Fan board.
Check the voltage at CNVDC on the Fan board while the inverter is stopped and if it is less than 220 V, check the following
items.
1) Check the CNVDC connector connection.
(3) Control board failure
Confirm that a voltage of 208-230 VAC is applied to the connector CN505 on the control board during inverter operation.
->If voltage is absent, check the control board, fuse F01, or (F1, F2). If no problems are found, replace the control board.
Refer to section - 6 - "Inverter" under part [4] "Trouble shooting principal parts" for error codes related to the
inverter.(page 196)
HWE0716A
- 135 -
GB