Mitsubishi Electric PUZ-A12NKA7 Service Manual page 38

Check code Abnormal points and detection method
Indoor/outdoor unit communication error
(Signal receiving error)
(Outdoor unit)
E8 (1) Abnormal if outdoor controller circuit
(6840) board could not receive anything nor-
mally for 3 minutes.
Indoor/outdoor unit communication error
(Transmitting error) (Outdoor unit)
(1) Abnormal if "0" receiving is detected 30
E9 times continuously though outdoor con-
(6841) troller circuit board has transmitted "1".
(2) Abnormal if outdoor controller circuit
board could not find blank of transmission
path for 3 minutes.
Non defined check code
EF This code is displayed when non defined
(6607 check code is received.
or
6608)
Serial communication error
1. A bnormal if serial communication
between outdoor controller circuit board
and outdoor power circuit board is
defective.
Ed
(0403)
2. A bnormal if communication between
outdoor controller circuit board and
M-NET board is not available.
Pipe temperature
<Cooling mode>
Detected as abnormal when the pipe tempera-
ture 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) [ −5.4˚F [−3:]
TH: Lower temperature between liquid pipe tempera-
ture and condenser/evaporator temperature
<Heating mode>
P8
When 10 seconds have passed after the compressor
starts operation and the hot adjustment mode has
finished, the unit is detected as abnormal when con-
denser/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: 5.4˚F [3:] [ (Condenser/
evaporator temperature (TH5) −
intake temperature (TH1))
OCH636A
Case
1 Contact failure of indoor/out-
door unit connecting wire
2 Defective communication circuit
of outdoor controller circuit board
3 Defective communication circuit
of indoor controller board
4 Noise has entered into indoor/
outdoor unit connecting wire.
1 Indoor/outdoor unit connecting
wire has contact failure.
2 Defective communication circuit
of outdoor controller circuit board
3 Noise has entered power supply.
4 Noise has entered indoor/out-
door unit connecting wire.
1 Noise has entered transmission
wire of remote controller.
2 Noise has entered indoor/out-
door unit connecting wire.
3 Outdoor unit is not a power-
inverter models.
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
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
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.
38
judgment and action
1 Check disconnection or looseness of indoor/
outdoor unit connecting wire of indoor or out-
door units.
2–4 Turn the power off, and on again to
check. Replace indoor controller board or
outdoor controller circuit board if abnormal-
ity is displayed again.
1 Check disconnection or looseness of indoor/
outdoor unit connecting wire.
2–4 Turn the power off, and on again to
check. Replace outdoor controller circuit
board if abnormality is displayed again.
12 Turn the power off, and on again to check.
Replace indoor controller board or outdoor
controller circuit board if abnormality is
displayed again.
3 Replace outdoor unit with power-inverter type
outdoor unit.
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
circuit board (CNMNT) and M-NET board (CN5).
2 Check disconnection, looseness, or breaking
of connection wire between outdoor controller
circuit board (CNMNT) and M-NET board (CND).
3 Check M-NET transmission wiring method.
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
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
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
ON
OFF
A-Control Service Tool SW2 setting
23Check converse connection of extension
pipe or converse wiring of indoor/outdoor
unit connecting wire.
)
2 3 4 5 6
ON
OFF
2 3 4 5 6
ON
OFF