Mitsubishi Electric CITY MULTI PUHY-400YMF-B, Service Handbook, Page: 170 / 204

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Checking code Meaning, detecting method Cause Checking method & Countermeasure
4230
4240
Radiator panel
overheat
protection
(Variable
capacity unit)
Overcurrent
protection
(Variable
capacity unit)
If the cooling fan stays ON for 5
minutes or longer during inverter
operation, and if THHS 100
°
C
is detected.
If IDC 66.5 A peak is detected
continuously for 10 minutes dur-
ing operation of the inverter after
5 or more seconds have passed
since the inverter started.
Check 1 connections, 2 contact at the
connectors and 3 for broken wires in
the following wiring.
MF1~CNFAN
If the fuse is defective, replace the
fuse.
To judge failure of the MF1, go to “In-
dividual Parts Failure Judgment Meth-
ods.”
To judge failure of the THHS, go to
error code “5110”.
If the air passage of the heat sink is
clogged, clear the air passage.
If none of the items in 1) to 5) 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).
Is the unit’s exhaust short cycling?
Clean the heat exchanger.
If the power supply voltage is less than
342 V, it is outside specifications.
If the external air temperature is over
than 43
°
C it is outside the specifica-
tions.
• Is the indoor unit capacity total
appropriate?
• Are the outdoor/indoor unit capac-
ity settings appropriate?
To judge failure of the THHS, go to the
item for error code “5110.”
To judge failure of the solenoid valve,
go to “Individual Parts Failure Judg-
ment Methods” for the “Solenoid
Valve.”
Check 1 connections, 2 contact at the
connectors and 3 for broken wires in
the following wiring.
TB1A ~ [F1, F2]~SCRM~CN04~
CNMF ~ MF
TB1A ~ CNTR1
CNU
~ SCRM
CNV ~ SCRM
CNW ~ SCRM
CNFC1~ CNFC2
Go to “Treating Fan Motor Related
Trouble.”
Go to “Treating Inverter/Compressor
Related Trouble.”
If none of the items in 1) to 10) is ap-
plicable, 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).
1) The wiring is defective.
2) The INV boar’s fuse (F01) is defec-
tive.
3) The cooling fan (MF1) is defective.
4) The THHS sensor is defective.
5) The air passage is clogged.
6) The INV board is defective.
1) Air passage Short Cycle.
2) The heat exchanger is clogged.
3) Power Supply Voltage.
4) External Air Temperature.
5) Capacity Setting Error.
6) The THHS sensor is defective.
7) The solenoid valves (SV1, 2) are
defective, or the solenoid valve drive
circuit is defective.
8) The wiring is defective.
9) Fan motor (MF) operation is defec-
tive.
10)The inverter/compressor is defective.
11)The circuit board is defective.