Fujitsu RDG30KHTAP Service Instruction page 52

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Trouble shooting 14
INDOOR UNIT Error Method:
Indoor Heat Ex. Thermistor Error
Detective Actuators:
Indoor unit Controller PCB Circuit
Heat Exchanger (MID) Thermistor
Forecast of Cause :
1. Connector failure connection
Check Point 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
Check Point 2 : Remove connector and check Thermistor resistance value
Thermistor Characteristics(Rough value)
Temperature (°C )
Resistance value (k )
Temperature (°C )
Resistance value (k )
If Thermistor is either open or shorted, replace it and reset the power.
OK
Check Point 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)
BLACK
1
1
CN8
BLACK
2
2
BLACK
1
1
CN32
2
2
BLACK
3
3
If the voltage does not appear, replace Controller PCB and execute the check operation again.
Indicate or Display:
Error code : 42
Detective details:
Indoor unit thermistor is open or short is detected always.
2. Thermistor failure
-30
-25
-20
1131.9
804.5
579.6
422.9
20
25
30
62.9
49.7
39.6
31.7
Room Temp. Thermistor
H/E Thermistor
Outdoor unit :
Mode Error L1 L2
3. Controller PCB failure
-15
-10
-5
312.3
233.2
176.0
35
40
45
50
25.6
20.8
17.1
02-15
L3
L4
2
5
15
: Light OFF
: Light ON
n : n times blinking
0
5
10
15
134.2
103.3
80.3
55
60
65
14.1
11.6
9.7
L5
L6
DC

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