Mitsubishi Electric CITY MULTI PUHY-P108 Service Handbook page 286

Error definition and error
Error Code
detection method
4108 Overcurrent
1. First detection
If 51C2 is started during
protection
the operation of No.2 com-
pressor, the outdoor unit
stops once, turns to anti-
restart mode for 3 minutes,
and restarts after 3 min-
utes. (Set value of the
over-current relay: 43A)
2. Second detection
If 51C2 is started again
within a minute after re-
starting in compliance with
1. above, the unit makes
an error stop and the error
code "4108" will appear.
3. There will be a minute
grace period of an error
stop when No.2 compres-
sor restarts after the out-
door unit stops and LED
indicates, which means the
grace period, will appear.
4115 Power supply The frequency cannot be
sync signal ab- determined when the
normality power is switched on.
4116 Motor abnor- 1. LOSSNAY
mality The motor keep run-
ning even if the pow-
er is OFF.
The thermal over-
load relay is ON.
(Only for the three-
phase model)
2. Indoor unit
If detected less than
180rpm or more than
2000rpm, the indoor
unit will restart and
keep running for 3
minutes.
If detected again, the
display will appear.
Cause
(1) Overload operation that
exceeds unit use limit
(2) Power supply error
Power-supply voltage
drop
Open phase of power
supply voltage
(3) Faulty wiring
(4) Compressor failure
Compressor open phase
or grounding fault
Compressor lock
(1) Power supply error
(2) A fuse is blown.
(3) Faulty wiring
(4) Main board failure
(1) Board failure
(2) Motor malfunction
(3) Solenoid switch malfunc-
tion
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[ IX Troubleshooting ]
Check method and remedy
Check the unit working condition.
Check the voltage of the power sup-
ply terminal block (TB1).
Check for open phase.
Check 52C2 connector and the wir-
ing.
Check the wiring and apply a meg-
ger to the compressor.
Start operation under no-load condi-
tions.
Remove the power wire on the com-
pressor-side, insulate the power line
and start operation.
-> The compressor is faulty if
52C2 normally turns on.
Check the voltage of the power sup-
ply terminal block (TB1).
Check the fuses on the main board
(F01 and F02).
Measure voltages of pin 5 of the
male connector (CN20) on the main
board and between pins 1 and 3 of
the male connector (CN21) on the
main board.
If the voltage (AC208 / 230V) is not
the same as the power supply volt-
age, the wiring is faulty.
If none of the items described above
is applicable, and if the trouble reap-
pears even after the power is
switched on again, replace the MAIN
board.
Replace the board.
Check for the motor and the solenoid
switch.