Fujitsu R410A Service Instruction page 37

Trouble shooting 12
OUTDOOR UNIT Error Method:
Compressor Thermistor Error
Detective Actuators:
Outdoor Unit Main PCB
Compressor Temperature Thermistor
Forecast of Cause:
1. Connector connection failure
Test 1 : Check connection of connector
Check if connector is removed.
Check if connector is erroneous connection.
Check if thermistor cable is open.
>> Upon correcting the removed connector or miss-wiring, reset the power.
OK
Test 2 : Remove connector and check thermistor resistance value
Thermistor characteristics (Approx. value)
Temperature (°C )
Temperature (°F )
Resistance value (k )
Temperature (°C )
Temperature (°F )
Resistance value (k )
If Thermistor is either open or shorted, replace it and reset the power.
OK
Test 3 : Check voltage of Main PCB (DC5.0V)
Make sure circuit diagram of outdoor unit and check terminal voltage at thermistor (DC5.0V)
BROWN
1 1
CN64 2 2
BROWN
3 3
BLUE
1 1
CN62 2 2
BLUE
3 3
BLACK
1 1
CN65 2 2
BLACK
3 3
BROWN
1 1
CN63 2 2
BROWN
3 3
If the voltage does not appear, replace Main PCB.
Indicate or Display:
Outdoor Unit : No indication
Indoor Unit : Operation lamp: 7 times Flash, Timer lamp: 2 times Flash
Economy lamp: Continuous flash.
ERROR CODE : [E : 72]
Detective details:
When Compressor Temperature Thermistor open or short-circuit
is detected at power ON or while running the compressor.
2. Thermistor failure
0 5 10 15
32 41 50 59
168.6 129.8 100.9 79.1
70 80 90 100
158 176 194 212
8.7 6.3 4.6 3.4
THERMISTOR
( COMPRESSOR TEMP. )
THERMISTOR
( OUTDOOR TEMP. )
THERMISTOR
( PIPE TEMP. )
THERMISTOR
( DISCHARGE TEMP. )
02-14
3. Main PCB failure
20 30 40 50
68 86 104 122
62.6 40.0 26.3 17.8
120
248
2.0
60
140
12.3