Fujitsu ASU18RLF Service Instructions Manual page 67

Trouble shooting 22
OUTDOOR UNIT Error Method:
Heat Ex. OUT Thermister Error
Detective Actuators:
Outdoor unit main PCB circuit
Heat Ex. temperature thermistor
Forecast of Cause:
1. Connector connection failure 2.Thermistor failure 3. Main PCB failure
Test 1 : Check connection of Connector
Check if connector is removed.
Check 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)
BLACK
1 1
CN61 2 2
BLACK
3 3
1 1
BLACK
CN62 2 2
BLACK
3 3
BLACK
1 1
BLACK
2 2
CN63
BLACK
3 3
BLACK
4 4
If the voltage does not appear, replace Main PCB.
Indicate of Display:
Indoor Unit
Operation lamp : 7 time Flash
Timer lamp
ERROR CODE : [E : 73]
Detective details:
When Heat Ex. temperarture thermistor open or short-circuit is detected
at power ON or while running the compressor.
-30 -20
-10 0
-22 -4 32
14
95.58 50.31 27.81 16.05
60 70 80
140 158 176
1.19 0.84 0.61
THERMISTOR
( OUTDOOR TEMP. )
THERMISTOR
( HEX OUT TEMP. )
THERMISTOR
( DISCHARGE TEMP. )
THERMISTOR
( COMP TEMP. )
02-27
Outdoor Unit
A
: 3 time Flash
7
: Light ON
10 20 30
50
68 86
9.63 5.98 3.84
Monitor
B C D E F
3
: Light OFF n : n time blinking
40 50
104 122
2.53 1.71