Mitsubishi Electric CITY MULTI PUHY-400YMF-C Service Handbook page 161

Checking code Meaning, detecting method
4106 Power off 1 Cannot operate because the
abnormality constant capacity unit is dis-
(Variable connected from the power
capacity unit) source.
4108 Over-current 1 First detection
Protection If the 51C2 is operated during
(Outdoor unit) operation of the No. 2 or No. 3
compressor the outdoor unit
will temporarily stop. After 3
minutes, it will restart.
2 Second detection
After 1 minute since the
above restart, if the 51C2
operates again there will be
an error stop, and "4108" will
be displayed.
3 After the outdoor unit stops
and the No. 2 compressor re-
starts there will be 1 minute
during which the unit is in pre-
liminary error stop mode. The
preliminary error stop display
will blink on the LED.
4115 Power supply The frequency cannot be deter-
sync signal mined when the power is switched
abnormality on.
(The power supply's frequency
cannot be detected. The outdoor
fan cannot be controlled by phase
control.)
4116 Fan speed (Detects only for PKFY-VAM)
abnormality 1. Detecting fan speed below
(motor 180rpm or over 2000rpm dur-
abnoramlity) ing fan operation at indoor unit
(first detection) enters into the
3-minute restart prevention
mode to stop fan for 30 sec-
onds.
2. When detecting fan speed be-
low 180rpm or over 2000rpm
again at fan returning after 30
seconsd from fan stopping, er-
ror stop (fan also stops) will be
commenced displaying 4116.
Cause
1) Power cord problem
(constant capacity unit is discon-
nected from the power source)
2) Power board fuse (F01, F02) is
blown.
3) Power board is defective
4) Control board is defective
1) Heavy-load operations exceeding the
unit's capacity.
2) Power source abnormality
a. Power source voltage drop
b. Power source voltage defect
3) Defective power cord
4) Defective compressor
a. Compressor open phase, earth
fault
b. Compressor lock-up
1) There is an open phase in the power
supply (L1, L2, L3, N).
2) The power supply voltage is dis-
torted.
3) A fuse is defective.
4) T01 is defective.
5) The circuit board is defective.
1) Slipping off of fan speed detect-
ing connector (CN33) of indoor
controller board.
2) Slipping off of fan output connec-
tor (FAN1) of indoor power board.
3) Disconnection of fan speed
detecting connector (CN33) of
indoor controller board, or that of
fan output connector (FAN1) of
indoor power board.
4) Filter cologging.
5) Trouble of indoor fan motor.
6) Faulty fan speed detecting circuit
of indoor controller board, or
faulty fan output circuit of indoor
power board.
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Checking method & Countermeasure
Measure the voltage in each part of
the constant capacity unit
1 Power source terminal block(TB1)
2 Power board (CN20)
3 Control board
• Confirm unit operation conditions
• Voltage check on power source
terminal block TB1
• Open phase check
• 52C2 connector, power cord check
• Power cord check, compressor
resistance check. (Mega-check)
• Operate in no-load status.
• Remove the compressor power
cord, check the power cord
insulation and operate.
If there is no abnormality
when 52C2 is turned ON, the
compressor is defective.
Check before the breaker, after the
breaker or at the powersupply
terminal blocks TB1A, and if there
is an open phase, correct the
connections.
the power supply voltage waveform
If
is distorted from a sine wave, improve
the power supply environment.
If F1 on the MAIN board, or F3 is
melted, (Resistance between both
ends of the fuse is ), replace the
fuses.
To judge failure of the T01, go to
"Individual Parts Failure Judgment
Methods."
If none of the items in 1) to 4) is
applicable, and if the trouble
reappears even after the power is
switched on again, replace the MAIN
board (when replacing the circuit
board, be sure to connect all the
connectors, ground wires, etc.
securely).
• Confirm slipping off of connector
(CN33) on indoor controller
board.
• Confirm slipping off of connector
(FAN1) on indoor power board.
• Check wiring for disconnection.
• Check filter.
• Check indoor fan motor.
• When aboves have no trouble.
1) For trouble after operating fan.
Replace indoor controller board.
If not remedied, replace indoor
power board.
2) For trouble without operating fan.
Replace indoor power board.