Mitsubishi Electric CITY MULTI PUHY-400YMF-B Service Handbook page 169

Checking code Meaning, detecting method
1 If IDC
4210 Breaking of
overcurrent tected during inverter opera-
(Variable tion.
capacity unit) 2 If the voltage of the INV
board's sensor circuit input is
what it should not normally be.
1 If VDC
4220 Bus voltage
abnormality during inverter operation.
2 If VDC
(Variable
capacity unit) during inverter operation.
103 A peak is de- 1) The power supply voltage is abnor-
mal.
2) The wiring is defective.
3) The inverter/compressor is defective.
400 V is detected 1) The power supply voltage is abnor-
mal.
800 V is detected
2) The wiring is defective.
3) The rush current prevention resistors
(R1, 5) are defective.
4) The electromagnetic contactor (52C)
is defective.
5) The diode stack (DS) is defective.
6) The reactor (DCL) is defective.
7) The inverter output is grounded.
8) The circuit board is defective.
–166–
Cause Checking method & Countermeasure
• Check if an instantaneous power
failure or power failure, etc. has
occurred.
• Check if the voltage is the rated
voltage value.
Check 1, the connections, 2, contact
at the connectors, 3 tightening torque
at screw tightened portions, 4, wiring
polarities, 5, for broken wires, and 6,
for grounding in the following wiring.
TB1A ~ DS ~ [52C, R1, R5] ~ [C2,
C3] ~ TRM Wiring
TRM ~ CNVDC Wiring
TRM ~ Compressor Wiring
[CN2-1, CN2-2, CN2-3, CN3]
~ TRM Wiring
* Check if the wiring polarities are as
shown on the wiring diagram plate.
* Check the coil resistances and in-
sulation resistance of the compres-
sor.
Go to "Treatment of Inverter/Compres-
sor Related Trouble."
• Check if an instantaneous stop or
power failure, etc. has occurred.
• Check if the voltage is the rated
voltage value.
Check 1, the connections, 2, contact
at the connectors, 3 tightening torque
at screw tightened portions, 4, wiring
polarities, 5, for broken wires, and 6,
for grounding in the following wiring.
TB1A ~ DS ~ [52C, R1, R5] ~ [C2, C3]
~ TRM Wiring
TRM ~ CNVDC Wiring
* Check if the wiring polarities are as
shown on the wiring diagram plate.
To judge failure of R1 and R5, go to
"Individual Parts Failure Judgment
Methods."
To judge failure of the 52C, go to "Indi-
vidual Parts Failure Judgment Meth-
ods."
To judge failure of the DS, go to "Indi-
vidual Parts Failure Judgment Meth-
ods."
To judge failure of the DCL, go to "In-
dividual Parts Failure Judgment Meth-
ods."
• Check the wiring between the TRM
and the compressor.
• Check the compressor's insulation
resistance.
If none of the items in 1) to 7) is appli-
cable, and if the trouble reappears
even after the power is switched on
again, replace the INV board (when
replacing the circuit board, be sure to
connect all the connectors, ground
wires, etc. securely).