Mitsubishi Electric PUHZ-SW75VAA-SC Service Manual page 30

Abnormal point and detection method
Check code
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) − room temperature
(TH1) [ −3 :
TH: Lower temperature between liquid pipe
temperature and condenser/evaporator
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 range : 3: [ (Condenser/
Evaporator temperature(TH5)−
room temperature(TH1))
OCH651A
Cause
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.
30
Judgment and action
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
23 Check 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