Fujitsu AOU30RLXEH, Service Instruction

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Trouble shooting 21
OUTDOOR UNIT Error Method:
Heat Ex. Liquid Temp.
Thermistor Error
Indoor Unit :
Operation lamp: 7 times Flash,
Timer lamp : 3 times Flash
ERROR CODE : [E : 73]
n: n times blinking : Light ON : Light OFF
Heat ex. liquid temp. thermistor
Detective Actuators: Detective details:
Indicate of Display:
Pipe (MID) Temp. Thermistor
Pipe Temp. Thermistor
BLACK
BLACK
1
2
3
4 1
2
3
4
5 5
CN63
BLACK
BLACK
Test 2 : Remove connector and check Thermistor resistance value
Thermistor Characteristics(Rough value)
If Thermistor is either open or shorted, replace it and reset the power.
Test 1 : Check connection of Connector
Check if connector is loose or removed
Check erroneous connection
Check if thermistor cable is open
>>Reset Power when reinstalling due to removed connector or incorrect wiring.
OK
OK
Test 3 : Check Voltage of Controller PCB (DC 5.0V)
Make sure circuit diagram of each indoor unit and check terminal voltage at Thermistor (DC5.0V)
If the voltage does not appear, replace Controller PCB and execute the check operation again.
Temperature ( °C )
Temperature ( °F )
-10 0 10 20 30 40 50
14 32 50 68 86 104 122
27.81
-30
-22
95.58
-20
-4
50.31 16.05 103.34 9.63 3.84 2.53 1.71
Resistance value (k )
Temperature ( °C )
Temperature ( °F )
80 90
176 194
0.61
60
140
1.19
70
158
0.84 0.45
Resistance value (k )
1. Connector connection failure, open 2. Thermistor failure 3. Main PCB failure
Forecast of Cause:
Outdoor unit :
POWER
MODE
ERROR
2
7
(L1) (L2) (L6) (L5) (L4) (L3)
13
PUMP
DOWN
LOW
NOISE
PEAK
CUT
02-24
When Heat exchanger liquid temperature thermistor open or short-circuit is
detected at power ON or while running compressor.