Mitsubishi City Multi PEFY-P72NMHSU-E Technical & Service Manual page 53

3. DC fan motor (fan motor/INV board)
If there are problems only with the fan motor, replace the fan motor only.
(Fan motor failure will cause an overcurrent to pass through the inverter, but the inverter is protected from damage with the
protection function that will stop the inverter when an overcurrent is detected.)
If the inverter fails, replace the failed components on the inverter.
If both the fan motor and inverter fail, replace the fan motor and all applicable parts on the inverter.
1. Troubleshooting the inverter-related problems
Error codes and symptoms
[1] Inverter-related errors
4255, 4225, 4235, 5110, 5305
[2] Main power breaker is tripped.
[3] The main earth leakage breaker
is tripped.
[4] Only the fan motor is inoperative. Check the display on the remote controller. If the fan is in operation, proceed to
[5] The fan motor vibrates excessive-
ly or makes abnormal sounds.
[6] Peripheral devices pick up electri-
cal noise.
[7] Accidental malfunction (due to
external noise)
1) Inside the inverter is a large capacity electrolytic capacitor, and the residual voltage that remains after the main power is turned
off presents a risk of electric shock. Before checking the inverter-related parts, turn off the main power, keep it turned off for
at least 10 minutes, and check that the voltage at both ends of the main capacitor (C015, C016) has dropped to a safe level.
Measure the voltage at both ends of the electrolytic capacitor at the check point where "CHECK VOLTAGE" is written in the
left top area of the NF board.
2) The IPM on the inverter becomes damaged if there are loose screws or connectors. When a problem occurs after replacing
components, faulty wiring is often the cause of the problem. Check the wiring, screws, connectors, and Fasten terminals for
proper connection.
3) Do not plug or unplug the inverter connectors while the main power is turned on, as this will result in damage to the circuit
board.
4) Electric current sensor will break if a current is passed through the sensor without it being connected to the circuit board. Con-
nect the current sensor to the appropriate connectors on the circuit board before operating the inverter.
HWE10170
Check the error history on the outdoor unit circuit board LED.
1) Check the breaker capacity.
2) Check the electric circuits other than the inverter circuits for short-circuit and
ground fault.
3) If no problems are found with items 1) and 2), see 3.-[1].
1) Check the capacity and the sensitivity current of the earth leakage breaker.
2) Insulation resistance failure of the electrical components other than the in-
verter
3) If no problems are found with items 1) and 2), see 3.-[1].
section 2.-[2] and 2.-[3].
See 2.-[2] and 2.-[3].
1) Check that the power wire to the peripheral devices are not routed adjacent
to the power wire to the indoor unit.
2) Check that the inverter output wiring is not routed adjacent to the power wire
or transmission line.
3) Check that a shielded cable is used if required. Check that the shield is prop-
erly grounded.
4) Insulation resistance failure of the electrical components other than the in-
verter
5) Connect the unit to a different power supply circuit.
6) If the problem appeared suddenly, there is a possibility that the inverter output
line had a ground fault. See section 2.-[2] and 2.-[3].
For problems other than the ones listed above, consult your dealer.
1) Check that the unit is properly grounded.
2) Check that a shielded cable is used if required. Check that the shield is prop-
erly grounded.
3) Check that the transmission line or wiring to external devices are not routed
adjacent to the power wires or are placed in the same conduit with them.
For problems other than the ones listed above, consult your dealer.
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Check items
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