Mitsubishi Electric PUHY-P200 Service Handbook page 105

Checking code Meaning, detecting method
4103 Reverse 1. The operation cannot be
phase started because of the
abnormality reserve phase of one of the
power lines (L1, L2 or L3).
2. When turning on the power,
the operation cannot be
started because of the open
phase of one of the power
lines (L1 or L2).
4108 Over-current 1. First detection
protection If 51C2 is started during the
operation of No.2 compressor,
the outdoor unit stops once,
turns to anti-restart mode for
3 minutes, and restarts after
3 minutes. (Set value of the
over-current relay: 55A)
2. Second detection
If 51C2 is started again within
a minute after restarting 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 compressor restarts
after the outdoor unit stops
and LED indicates, which
means the grace period, will
appear.
Cause
(1) Faulty wiring
(2) Main board failure
(1) Power supply failure
a) Open phase of power
supply voltage
b) Power supply voltage drop
(2) Faulty wiring
Between the power supply
terminal block (TB1) and the
main boards (CN20 and 21)
(3) Blown fuse
(4) Main board failure
(1) Overload operation that
exceeds unit use limit
(2) Power supply error
a) Power-supply voltage drop
b) Power-supply voltage
open phase
(3) Wiring defect
(4) Compressor malfunction
a) Compressor open phase,
grounding fault
b) Compressor lock
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Checking method & Countermeasure
· Check whether the phase of
the power supply terminal
block (TB1) is normal.
· Check the wiring between the
power supply terminal block
(TB1) and the main boards
(CN20 and CN21).
TB1 Pin
L1 CN20 5 Pin
N CN21 3 Pin
L2 CN21 1 Pin
If the above faults are not found,
the main board is faulty.
Check the input resistance of
the power supply terminal block
(TB1).
· Check the voltage of No.5 pin
of the main board connector
(CN20) and the voltage
between No.1 and 3 pin of
CN21.
· If the voltage is not the same
as the power supply voltage,
the wiring is faulty.
Check whether the fuses of the
main board (both F01 and F02)
are not blown.
If the above faults are not found,
the main board is faulty.
Check the unit working condition.
Check the voltage of the power-
supply terminal block (TB1).
Check for open phase.
Check 52C2 connector and the
wiring.
Check the wiring and apply a
megger to the compressor.
Start operation under no-load
conditions.
Remove the power wire on the
compressor-side, insulate the
power line and start operation.
→ The compressor is faulty if
52C2 normally turns on.