Abnormal Power Synchronous Signal; Pfc Error; Compressor Overcurrent Interruption; Current Sensor Error - Mitsubishi Electric SUZ-KA24NAHZ Service Manual

Check Code Abnormal point and detection method
Detailed Abnormal power synchronous
codes
signal
• No input of power synchronous
signal to power circuit board
• Power synchronous signal
of 44 Hz or less, or 65 Hz or
more is detected on power
circuit board.
08
PFC error (Overvoltage/
U9
Undervoltage/Overcurrent)
(4220)
• PFC detected any of the fol-
lowing:
a) Increase of DC bus voltage
as follows: 430 V
b) Decrease in PFC control
voltage to 13 VDC or lower
10
c) Increase in input current as
follows.
KA24: 42 A peak
KA30/36: 62 A peak

Compressor overcurrent interruption

(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
after compressor starts operating.
UF
(4100)

Current sensor error

• It is abnormal for 38 A the input current or
10 seconds continuous 34 A or more.
UH
(5300)
Overheat protection
Abnormal if outdoor pipe thermistor (TH3),
condensing temperature T
Ud
158˚F [70°C] or more during compressor
(1504)
operation.
Abnormal pressure of 63HS
Abnormal if 63HS detects 14.5 PSIG [0.1
MPa] or less.
Detection is inoperative for 3 minutes after
UE
compressor starting and 3 minutes after
(1302)
and during defrosting.
63HS: High pressure sensor
OCH754A
1 Distortion of power source
voltage, noise superimposition
2 Disconnection or loose
connection of earth wiring
3 Disconnection or loose
connection of CN2 on the
outdoor power circuit board /
controller circuit board
4 Defective power synchronous
signal circuit in outdoor
controller circuit board
5 Defective power synchronous
signal circuit in outdoor power
circuit board
1 Abnormal increase in power
source voltage
2 Decrease in power source
voltage, instantaneous stop
3 Disconnection of compressor
wiring
4 Misconnection of reactor (DCL)
5 Defective outdoor power circuit
board
6 Defective reactor (DCL)
7 Disconnection or loose
connection of CN2 on the
outdoor power circuit board/
controller circuit board
1 Stop valve is closed.
2 Decrease of power supply
voltage
3 Looseness, disconnection or
converse of compressor wiring
connection
4 Defective compressor
5 Defective outdoor power board
6 DIP switch setting difference of
outdoor controller circuit board.
1 Defective circuit of current
sensor on outdoor power circuit
board
2 Decrease of power supply
voltage
1 Defective outdoor fan (fan
motor) or short cycle of outdoor
detects unit during cooling operation
63HS
2 Defective outdoor pipe thermis-
tor (TH3), condensing temper-
ture T
63HS
3 Defective outdoor controller board
1 Disconnection or contact
failure of connector (63HS) on
the outdoor controller circuit
board
2 Defective pressure sensor
3 Defective outdoor controller
circuit board
31
Cause
1 Check the field facility for the power supply.
2 Check earth wiring.
3 Check CN2 wiring.
4 Replace outdoor controller circuit board.
5 Replace outdoor power circuit board.
12 Check the field facility for the power sup-
ply.
3 Correct the wiring (U·V·W phase) to
compressor. Refer to "10-8. TEST POINT
DIAGRAM".
4 Correct the wiring (U·V·W phase) or reactor
(DCL).
5 Replace outdoor power circuit board.
6 Replace reactor (DCL).
7 Check CN2 wiring.
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U
compressor. Refer to "10-8. TEST POINT
DIAGRAM" (Outdoor power circuit board).
4 Check compressor.
Refer to "10-5. HOW TO CHECK THE PARTS".
5 Replace outdoor power circuit board.
6 Check the dip switch setting of outdoor con-
troller circuit board. Refer to "Model Select" in
"1) Function of switches" in "10-9. FUNCTION
OF SWITCHES, CONNECTORS AND
JUMPERS".
1 Replace outdoor power circuit board.
2 Check the facility of power supply.
1 Check outdoor unit air passage.
23 Turn the power off and on again to check
the check code. If U4 is displayed, follow the
U4 processing direction.
1 Check connection of connector (63HS) on
the outdoor controller circuit board.
Check breaking of the lead wire for 63HS.
2 Check pressure by microprocessor.
(Pressure sensor/ 63HS)
(SW2: Refer to "10-9. FUNCTION OF
SWITCHES, CONNECTORS AND
JUMPERS".)
3 Replace outdoor controller board.
Judgment and action
V W phase) to
• •