Mitsubishi Electric TRANE TPKA0A0121HA70A Service Manual page 22

Check code Abnormal point and detection method
Freezing/overheating protection is work-
ing
1 Freezing protection (Cooling mode)
• In case when
outside temperature > −4°F [−20:]
The unit is in 6-minute resume preven-
tion mode if pipe <liquid or condenser/
evaporator> temperature stays under
−5°F [−15:] for 3 minutes, 3 minutes
after the compressor started.
Abnormal if it stays under −5°F [−15:]
for 3 minutes again within 16 minutes
after 6-minute resume prevention mode.
• In case when
outside temperature [ −4°F [−20:]
The unit is in 6-minute resume preven-
P6
tion mode if pipe <liquid or condenser/
evaporator> temperature stays under
−31°F [−35:] for 3 minutes, 3 minutes
after the compressor started.
Abnormal if it stays under −31°F [−35:]
for 3 minutes again within 16 minutes
after 6-minute resume prevention mode.
2 Overheating protection (Heating mode)
The unit is in 6-minute resume
prevention mode if pipe <liquid or con-
denser/evaporator> temperature is
detected as over 158°F [70:] after the
compressor started. Abnormal if the tem-
perature of over 158°F [70:] is detected
again within 30 minutes after 6-minute
resume prevention mode.
Pipe temperature
<Cooling mode>
Detected as abnormal when the pipe tem-
perature is not in the cooling range 3 min-
utes 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: −5.4°F [−3°C] ] (TH−TH1)
TH: Lower temperature between liquid pipe
temperature (TH2) and condenser/
evaporator temperature (TH5)
TH1: Intake 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 heat-
ing 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°C] [ (TH5−TH1)
OCHT637
Cause
(Cooling or drying mode)
1 Clogged filter (reduced airflow)
2 Short cycle of air path
3 Low-load (low temperature)
operation out of the tolerance
range
4 Defective indoor fan motor
• Fan motor is defective.
• Indoor controller board is defec-
tive.
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 Overload (high temperature)
operation out of the tolerance
range
4 Defective indoor fan motor
• Fan motor is defective.
• Indoor controller board is defec-
tive.
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.
22
*1 only P-series outdoor unit
Countermeasure
(Cooling or drying mode)
1 Check clogs of the filter.
2 Remove shields.
4 Refer to "9-6. HOW TO CHECK THE
PARTS".
5 Check outdoor fan motor.
67 Check operating condition of refriger-
ant
circuit.
(Heating mode)
1 Check clogs of the filter.
2 Remove shields.
4 Refer to "9-6. HOW TO CHECK THE
PARTS".
5 Check outdoor fan motor.
6–8Check operating condition of refriger-
ant circuit.
1–4 Check pipe <liquid or condenser/
evaporator> temperature with room
temperature display on remote con-
troller and outdoor controller circuit
board.
Pipe <liquid or condenser/evapora-
tor> temperature display is indicated
by setting SW2 of outdoor controller
circuit board as follows.
(
*1
Conduct temperature check with outdoor
controller circuit board after connecting
'A-Control Service Tool(PAC-SK52ST)'.
23Check converse connection of exten-
sion pipe or converse wiring of indoor/
outdoor unit connecting wire.
(