Mitsubishi Electric PEAD Series Service Manual page 32

TROUBLESHOOTING
Error Code Abnormal point and detection method
Freezing/overheating protection is
working
1 Freezing protection (Cooling mode)
The unit is in six-minute resume
prevention mode if pipe <liquid or
condenser/evaporator> temperature
after the compressor started. Abnormal
minutes again within 16 minutes after
six-minute resume prevention mode.
2 Overheating protection (Heating mode)
The units is in six-minute resume
prevention mode if pipe <Liquid or
condenser / evaporator> temperature is
compressor started. Abnormal if the
detected again within 10 minutes after
six-minute resume prevention mode.
P6
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 :
TH: Lower temperature between: liquid
pipe temperature (TH2) and
condenser/evaporator temperature
(TH5)
P8 TH1: Intake 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 :
HWE16080
Cause
(Cooling or drying mode)
1 Clogged filter (reduced airflow)
2 Short cycle of air path
3 Low-load (low temperature)
operation beyond the tolerance
range
4 Defective indoor fan motor
Fan motor is defective.
Indoor controller board is
defective.
5 Defective outdoor fan control
6 Overcharge of refrigerant
7 Defective refrigerant circuit
(clogs)
(Heating mode)
1 Clogged filter (reduced airflow)
2 Short cycle of air path
3 Over-load (high temperature)
operation beyond the tolerance
range
4 Defective indoor fan motor
Fan motor is defective.
Indoor controller board is
defective.
5 Defective outdoor fan control
6 Overcharge of refrigerant
7 Defective refrigerant circuit
(clogs)
8 Bypass circuit of outdoor unit is
defective.
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.
32
Countermeasure
(Cooling or drying mode)
1 Check clogging of the filter.
2 Remove shields.
4 Refer to 10-8. DC Fan motor (FAN
MOTOR/ INDOOR CONTROLLER
BOARD)
5 Check outdoor fan motor.
6 7 Check operating condition of refrigerant
circuit.
(Heating mode)
1 Check clogs of the filter.
2 Remove shields.
4 Refer to 10-8. DC Fan motor (FAN
MOTOR/ INDOOR CONTROLLER
BOARD)
5 Check outdoor fan motor.
6~8 Check operating condition of refrigerant
circuit.
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.
(
Conduct temperature check with outdoor
controller circuit board after connecting
2 3 Check converse connection of
extension pipe or converse wiring of
indoor/outdoor unit connecting wire.
(