Mitsubishi Electric Mr.Slim PCA-M35KA2 Service Manual page 24

Check Code Abnormal point and detection method
Freezing/overheating protection is
operating
Freezing protection (Cool mode)
The unit is in 6-minute resume
prevention mode if pipe <liquid or
condenser/evaporator> temperature
stays under −15˚C for 3 minutes, 3
minutes after the compressor started.
Abnormal if it stays under −15˚C for 3
minutes again within 16 minutes after
6-minute resume prevention mode.
P6
Overheating protection (Heat mode)
The unit is in 6-minute resume
prevention mode if pipe <liquid or
condenser/evaporator> temperature
is detected as over 70˚C after the
compressor started. Abnormal if the
temperature of over 70˚C is detected
again within 30 minutes after 6-minute
resume prevention mode.
Pipe temperature
<Cool 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
dry mode.
Cooling range: −3˚C
TH: Lower temperature between liquid pipe
temperature (TH2) and condenser/
evaporator temperature (TH5)
P8 TH1: Intake temperature
<Heat 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 defrost
mode is over.)
Heating range: 3˚C
OCH752
(Cool or dry mode)
Clogged filter (reduced airflow)
Short cycle of air path
Low-load (low temperature)
operation out of the tolerance
range
Defective indoor fan motor
• Fan motor is defective.
• Indoor controller board is
defective.
Defective outdoor fan control
Overcharge of refrigerant
Defective refrigerant circuit
(clogs)
(Heat mode)
Clogged filter (reduced airflow)
Short cycle of air path
Overload (high temperature)
operation out of the tolerance
range
Defective indoor fan motor
• Fan motor is defective.
• Indoor controller board is
defective.
Defective outdoor fan control
Overcharge of refrigerant
Defective refrigerant circuit
(clogs)
Bypass circuit of outdoor unit
is defective.
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
Reverse connection of
(TH−TH1) extension pipe (on plural units
connection)
Reverse wiring of indoor/
outdoor unit connecting wire
(on plural units connection)
Defective detection of indoor
room temperature and pipe
<condenser/evaporator>
temperature thermistor
Stop valve is not opened
completely.
(TH5−TH1)
Cause
(Cool or dry mode)
Check clogs of the filter.
Remove blockage.
Refer to "9-6. HOW TO CHECK THE
PARTS".
Check outdoor fan motor.
Check operating condition of refrigerant
circuit.
(Heat mode)
Check clogs of the filter.
Remove blockage.
Refer to "9-6. HOW TO CHECK THE
PARTS".
Check outdoor fan motor.
– Check operating condition of refrigerant
circuit.
– Check pipe <liquid or condenser/evapo-
rator> temperature with room tempera-
ture 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)'.
Check reverse connection of extension
pipe or reverse wiring of indoor/outdoor
unit connecting wire.
Check the stop valve is opened completely.
24
Judgment and action
)