Mitsubishi Electric Mr.Slim PLA-RP3AA Service Manual page 28

Error Code Meaning of error code and detection method
Freezing/overheating protection is
working
1 Freezing protection (Cooling mode)
The unit is in six-minute resume preven-
tion mode if pipe <liquid or condenser-
evaporator> temperature stays under
-15: for three minutes, three minutes
after the compressor started. Abnormal
if it stays under -15: for three minutes
again within 16 minutes after six-minute
resume prevention mode.
2 Frost abnormality (Only for the combina-
tion with inverter-type outdoor unit)
Suspensive abnormal if unit operates in
frost prevention mode (below) for 9
minutes or more. After that, when frost
prevention mode is released and
compressor restarts its operation, unit is
not detected as abnormal if compressor
keeps operating for 20 minutes continu-
ously and abnormal if compressor stops
operating within 20 minutes and unit
operates in frost prevention mode for
more than 9 minutes again. (Not abnor-
P6
mal if unit stops operating in frost pre-
vention mode within 9 minutes)
<Frost prevention mode>
If pipe <liquid or condenser-evaporator>
temperature is 2: or below when 16
minutes has passed after compressor
starts operating, unit will start operating
in frost prevention mode which stops
compressor operation. After that, when
pipe <liquid or condenser-evaporator>
temperature stays 10: or more for 3
minutes, frost prevention mode will be
released and compressor will restart its
operation.
3 Overheating protection (Heating mode)
The units is in six-minute resume pre-
vention mode if pipe <condenser-evapo-
rator> temperature is detected as over
74: after the compressor started.
Abnormal if the temperature of over
74: is detected again within 10 minutes
after six-minute resume prevention
mode.
Abnormality of pipe temperature
(Cooling mode)
Detected as abnormal when the pipe tem-
perature is not in the cooling range 3 min-
utes later of compressor start and 6 min-
utes later of the liquid or condenser/evapo-
rator pipe is out of cooling range.
Note 1) It takes at least 9 min. to detect
abnormality.
Note 2) Abnormality P8 is not detected in
drying mode.
Cooling range- = TH – intake temperature
[ 3 deg
TH: Lower temperature between: liquid
pipe temperature and condenser/ evap-
orator temperature
P8
(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 operation = 3 deg [ (Condenser/
Evaporator temperature – intake
temperature)
Case
(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.
Control board is defective.
5 Defective outdoor fan control
(middle season, winter season)
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.
Control board is defective.
5 Malfunction of outdoor fan.
(Season when air conditioner
is not used.)
6 Overcharge of refrigerant
7 Defective refrigerant circuit
(clogs)
8 Bypass circuit of outdoor unit
is defective.
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-evapo-
rator> thermistor
• Defective refrigerant circuit
2 Converse connection of exten-
sion pipe (on plural units con-
nection)
3 Converse wiring of indoor/out-
door unit connecting wire (on
plural units connection)
4 Defective detection of indoor
room temperature and pipe
<liquid or condenser-evapora-
tor> temperature thermistor
5 Defective stop valve action
(It does not open fully.)
28
Judgment and action
(Cooling or drying mode)
1 Check clogs of the filter.
2 Remove shields.
4 Measure the resistance of fan motor's wind-
ing.
Measure the output voltage of fan's connec-
tor (FAN) on control board.
WThe control board should be normal when
a current of AC100V to 240V is detected
while fan motor is connected.
5 Check action of outdoor fan motor.
67Check operating condition of refrigerant cir-
cuit.
(Heating mode)
1 Check clogs of the filter.
2 Remove shields.
4 Measure the resistance of fan motor's wind-
ing.
Measure the output voltage of fan's connec-
tor (FAN) on control board.
WThe control board should be normal when
a current of AC100V to 240V is detected
while fan motor is connected.
5Check the operation of fan motor in outdoor
unit.
6~8Check operating condition of refrigerant
circuit.
14 Check pipe <liquid or condenser-evapora-
tor> temperature with room temperature
display on remote controller and outdoor
control board.
( In case of checking pipe temperature
with outdoor control board, be sure to
connect 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