Mitsubishi Electric City Multi CMH-WM250V-A, Service Handbook

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[7-6 Error Code Definitions and Solutions: Codes [4000 - 4999] ]
BS_07_E chapter 7 -
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7-6-13 Error Codes [4220, 4225, 4226] Detail Code 108
1. Error code definition
Abnormal bus voltage drop (Detail code 108)
2. Error definition and error detection method
If Vdc 289V or less is detected during Inverter operation. (S/W detection) (Outdoor unit)
If Vdc 150V or less is detected during Inverter operation. (S/W detection) (Hydro unit)
3. Cause, check method and remedy
Outdoor unit
(1) Power supply environment
Check the power-supply wiring for an open phase. Refer to item (5) in section [6-1 Read before Test Run].
Find out if there was a (momentary) power failure.
Check whether the power voltage (Between L1 and L2, L2 and L3, and L1 and L3) is 342V or less across all phases.
(2) Voltage drop detected
4220
INV35Y and INV37YC

Check the voltage at relay connector RYPN while the inverter is stopped.
If the voltage is 420 V or above, check the following items.
1) Check the LED monitor to see if the bus voltage is above 289 V, and replace the inverter board if it is 289 V or below.
2) Check the coil (L) connections and for broken wiring.
3) Check the wiring connections between noise filter board and INV board.
4) If the problem persists after reboot, replace the INV board.
If the voltage is below 420 V, check the following items.
1) Check the coil (L) connections and for broken wiring.
2) Check the wiring connections between noise filter board and INV board and between INV board and R1 through R5.
3) Check the in-rush current resistor. Refer to the following page(s). [8-10-18 Simple Check on Inverter Circuit Compo-
nents]
4) If the problem persists after reboot, replace the INV board.
INV42Y
 Check the voltage at relay connector RYPN while the inverter is stopped.
If the voltage is 420 V or above, check the following items.
1) Check the LED monitor to see if the bus voltage is above 289 V, and replace the inverter board if it is 289 V or below.
2) Check the coil (L) connections and for broken wiring.
3) Check the wiring connections between noise filter board and INV board and between INV board and capacitor board.
4) If the problem persists after reboot, replace the INV board.
If the voltage is below 420 V, check the following items.
1) Check the coil (L) connections and for broken wiring.
2) Check the wiring connections between noise filter board and INV board, between INV board and capacitor board, and
between INV board and R1 through R5.
3) Check the in-rush current resistor. Refer to the following page(s). [8-10-18 Simple Check on Inverter Circuit Compo-
nents]
4) If the problem persists after reboot, replace the INV board.
4225, 4226
 Check the voltage at relay connector RYPN while the inverter is stopped. If the voltage is below 420 V, check the following
items.
1) Check for proper connections of noise filter coil and DC reactor, and for broken wiring.
2) Check the wiring connections between INV board and FAN board.
3) Check item for 4220
Replace the FAN board if no problems are found.
 Check the voltage at connector RYPN while the inverter is stopped. If the voltage is 420 V or above, check the following items.
1) Check the state of the wiring connections between the INV board and the Fan board.
2) Check contents 4220
Replace the Fan board if no problems are found.
(3) Control board failure
Check that 12VDC is applied to connector CN72 on the control board while the inverter is operating. If voltage is absent or
the wrong voltage is applied, check the fuse F01. Replace the control board if no problems are found with the fuse.
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