43
OCH737
Check Code Abnormal points and detection method
Cause
Judgment and action
Ed
(0403)
Serial communication error
1
Abnormal if serial communication between
outdoor controller circuit board and out-
door power circuit board is defective.
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 circuit of
outdoor controller circuit board for
outdoor power circuit board
12
Check connection of each connector CN2
and CN4 between the outdoor controller
circuit board and the outdoor power cir-
cuit board.
3
Replace outdoor power circuit board.
4
Replace outdoor controller circuit board.
2
Abnormal if communication between
outdoor controller circuit board and
M-NET board is not available.
1
Breaking of wire or contact fail-
ure of connector between out-
door 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
Check disconnection, looseness, or breaking
of connection wire between outdoor control-
ler circuit board (CNMNT) and M-NET board
(CN5).
2
Check disconnection, looseness, or breaking
of connection wire between outdoor control-
ler circuit board (CNMNT) and M-NET board
(CND).
3
Check M-NET transmission wiring method.
P8
Pipe temperature
<Cooling mode>
Detected as abnormal when the pipe
temperature is not in the cooling range
3 minutes 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)−intake temperature (TH1)
[
−3
:
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/
evaporator pipe temperature is not in heating
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:
3
:
[
(Condenser/ Evaporator
temperature(TH5)−intake
temperature(TH1))
1
Slight temperature difference
between indoor room temperature
and pipe <liquid or condenser/
evaporator> temperature
thermistor
• Shortage of refrigerant
• Disconnected holder of
pipe <liquid or condenser/
evaporator> thermistor
• Defective refrigerant circuit
2
Converse connection of extension
pipe (on plural units connection)
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
completely.
1
–
4
Check pipe <liquid or condenser/
evaporator> temperature with room
temperature display on remote controller
and outdoor controller circuit board.
Pipe <liquid or condenser/evaporator>
temperature display is indicated by set-
ting SW2 of outdoor controller circuit
board as follows.
Conduct temperature check with outdoor
controller circuit board after connecting
‘A-Control Service Tool (PAC-SK52ST)’.
1
2
3
4
5
6
ON
OFF
1
2
3
4
5
6
ON
OFF
1
2
3
4
5
6
ON
OFF
1
2
3
4
5
6
ON
OFF
A-Control Service Tool SW2 setting
Temperature display of indoor liquid pipe
Indoor 1
Temperature display of indoor liquid pipe
Indoor 2
Temperature display of indoor condenser/
evaporator pipe Indoor 1
Temperature display of indoor condenser/
evaporator pipe Indoor 2
5
Check converse connection of extension
pipe or converse wiring of indoor/outdoor
unit connecting wire.
PL
Abnormal refrigerant circuit
During Cooling, Dry, or Auto Cooling
operation, the following conditions are
regarded as failures when detected for 1
second.
a) The compressor continues to run for 30 or
more seconds.
b) The liquid pipe temperature or the
condenser/evaporator temperature is 75°C
or more.
These detected errors will not be
cancelled until the power source is
reset.
1
Abnormal operation of 4-way valve
2
Disconnection of or leakage in
refrigerant pipes
3
Air into refrigerant piping
4
Abnormal operation (no rotation) of
indoor fan
· Defective fan motor
· Defective indoor control board
5
Defective refrigerant circuit
(clogging)
1
When this error occurs, be sure to
replace the 4-way valve.
2
Check refrigerant pipes for disconnection
or leakage.
3
After the recovery of refrigerant, vacuum
dry the whole refrigerant circuit.
4
Refer to "10-6. HOW TO CHECK THE
PARTS".
5
Check refrigerant circuit for operation.
To avoid entry of moisture or air into
refrigerant circuit which could cause
abnormal high pressure, purge air in
refrigerant circuit or replace refrigerant.
(
)
