Fujitsu ASU18RLF Service Instructions Manual page 70

Trouble shooting 25
OUTDOOR UNIT Error Method:
3-Way Valve Thermistor Error
Detective Actuators:
Outdoor unit main PCB circuit
3 Way valve 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)
For AOU36RLXFZH
BLACK
1 1
BLACK
2 2
BLACK
3 3
BLACK
4 4
CN64
BLACK
5 5
BLACK
6 6
BLACK
7 7
BLACK
8 8
BLACK
1 1
2 2
BLACK
3 3
BLACK
4 4
BLACK
5 5
CN65
BLACK
6 6
BLACK
7 7
BLACK
8 8
BLACK
9 9
If the voltage does not appear, replace Main PCB.
Indicate of Display:
Indoor Unit
Operation lamp : 7 time Flash
Timer lamp
ERROR CODE : [E : 76]
Detective details:
When 3 Way valve temperarture thermistor open or short-circuit is detected
at power ON or while running the compressor.
-30 -20
-10
-22 -4 32
14
1013.11 531.56 292.91 168.60
60 70 80
140 158 176
12.30 8.70 6.27
VALVE THERMISTOR A, B
2-WAY VALVE A
3-WAY VALVE A
2-WAY VALVE B
3-WAY VALVE B
VALVE THERMISTOR C, D
2-WAY VALVE C
3-WAY VALVE C
2-WAY VALVE D
3-WAY VALVE D
02-30
Outdoor Unit
A
: 6 time Flash
7
: Light ON
0 10 20 30
50
68 86
100.91 62.55 40.01
For AOU45RLXFZ
BLACK
1 1
BLACK
2 2
BLACK
3 3
BLACK
4 4
CN64 BLACK
5 5
BLACK
6 6
BLACK
7 7
BLACK
8 8
BLACK
1 1
BLACK
2 2
3 3
BLACK
4 4
BLACK
5 5
CN65
BLACK
6 6
BLACK
7 7
BLACK
8 8
BLACK
9 9
BLACK
1 1
BLACK
2 2
3 3
BLACK
4 4
BLACK
CN66 5 5
6 6
7 7
8 8
9 9
Monitor
B C D E F
6
: Light OFF n : n time blinking
40 50
104 122
26.34 17.79
VALVE THERMISTOR A, B
2-WAY VALVE A
3-WAY VALVE A
2-WAY VALVE B
3-WAY VALVE B
VALVE THERMISTOR C, D
2-WAY VALVE C
3-WAY VALVE C
2-WAY VALVE D
3-WAY VALVE D
VALVE THERMISTOR E
2-WAY VALVE E
3-WAY VALVE E