Non Defined Check Code; Serial Communication Error; Pipe Temperature; Cooling Mode - Mitsubishi Electric SUZ-KA24NAHZ Service Manual

Check Code
Abnormal point and detection method

Non defined check code

This code is displayed when non-defined
EF
check code is received.
(6607
or
6608)

Serial communication error

1. Abnormal if serial communication
between outdoor controller circuit board
and outdoor power circuit board is defec-
tive.
Ed
(0403)
2. Abnormal if communication between out-
door controller circuit board and M-NET
board is not available.

Pipe temperature

<Cooling mode>
Detected as abnormal when the pipe tem-
perature is not in the cooling range 3 min-
utes after compressor start and 6 minutes
after the liquid or condenser/evaporator
pipe is out of cooling range.
Note 1: It takes at least 9 minutes to detect.
Note 2: Abnormality P8 is not detected in
drying mode.
Cooling range: Indoor pipe temperature
(TH2 or TH5)−room temperature
(TH1) [ −5.4˚F [−3˚C]
TH: Lower temperature between liquid pipe
temperature and condenser/
evaporator temperature
<Heating mode>
When 10 seconds have passed after the
compressor starts operation and the hot
adjustment mode has finished, the unit is
detected as abnormal when condenser/
P8
evaporator pipe temperature is not in heat-
ing range within 20 minutes.
Note 3: It takes at least 27 minutes to
detect abnormality.
Note 4: It excludes the period of defrosting
(Detection restarts when defrosting
mode is over)
Heating range: −5.4˚F [−3˚C] [ (Condenser/
Evaporator temperature(TH5)−
room temperature(TH1))
OCH754A
Cause
1 Noise has entered transmission
wire of remote controller.
2 Noise has entered indoor/ out-
door unit connecting wire.
3 Outdoor unit is not inverter
model.
1 Breaking of wire or contact
failure of connector CN2
between the outdoor controller
circuit board and the outdoor
power circuit board
2 Breaking of wire or contact
failure of connector CN4
between the outdoor controller
circuit board and the outdoor
power circuit board
3 Defective communication circuit
of outdoor power circuit board
4 Defective communication cir-
cuit of outdoor controller circuit
board for outdoor power circuit
board
1 Breaking of wire or contact
failure of connector between
outdoor controller circuit board
and M-NET board
2 Contact failure of M-NET board
power supply line
3 Noise has entered into M-NET
transmission wire.
1 Slight temperature difference
between indoor room tempera-
ture and pipe <liquid or con-
denser/evaporator> tempera-
ture thermistor
• Shortage of refrigerant
• Disconnected holder of pipe
<liquid or condenser/
evaporator> thermistor
• Defective refrigerant circuit
2 Converse connection of exten-
sion pipe (on plural units con-
nection)
3 Converse wiring of indoor/
outdoor unit connecting wire
(on plural units connection)
4 Defective detection of indoor
room temperature and pipe
<condenser/evaporator>
temperature thermistor
5 Stop valve is not opened com-
pletely.
34
Judgment and action
12 Turn the power off, and on again to check.
Replace indoor controller board or outdoor
controller circuit board if abnormality is dis-
played again.
3 Replace outdoor unit with power inverter type.
12 Check connection of each connector CN2
and CN4 between the outdoor controller
circuit board and the outdoor power circuit
board.
3 Replace outdoor power circuit board.
4 Replace outdoor controller circuit board.
1 Check disconnection, looseness, or breaking of
connection wire between outdoor controller cir-
cuit board (CNMNT) and M-NET board (CN5).
2 Check disconnection, looseness, or breaking of
connection wire between outdoor controller cir-
cuit board(CNVMNT) and M-NET board (CND).
3 Check M-NET transmission wiring method.
1–4 Check pipe <liquid or condenser/
evaporator> temperature with room tem-
perature display on remote controller and
outdoor controller circuit board.
Pipe <liquid or condenser/evaporator>
temperature display is indicated by setting
SW2 of outdoor controller circuit board as
follows.
(
Conduct temperature check with outdoor
controller circuit board after connecting
'A-Control Service Tool(PAC-SK52ST)'.
Temperature display of indoor condenser/
Temperature display of indoor liquid pipe
evaporator pipe Indoor 1
Indoor 1
1 2 3 4 5 6 1 2
ON
OFF
Temperature display of indoor condenser/
Temperature display of indoor liquid pipe
evaporator pipe Indoor 2
Indoor 2
1 2 3 4 5 6 1 2
ON
OFF
A-Control Service Tool SW2 setting
23 Check converse connection of extension
pipe or converse wiring of indoor/outdoor
unit connecting wire.
5 Check the stop valve is opened completely.
)
3 4 5 6
ON
OFF
3 4 5 6
ON
OFF