Fujitsu AOYG45LAT8 User Manual page 107

Trouble shooting 42
Branch Box Error Method:
Indoor Unit A, B, C, liquid pipe
thermistor error (CN309 / 310)
Detective Actuators:
Branch Box Controller PCB
Indoor unit A,B,C Liquid pipe Thermistor
Forecast of Cause :
1. Connection failure 2. Thermistor failure 3. Controller PCB failure
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 (DC5.0V)
Make sure circuit diagram of each indoor unit and check terminal voltage at Thermistor (DC5.0V)
Schematic Diagram (Connector connection)
If the voltage does not appear, replace Controller PCB .
Indicate or Display:
Outdoor Unit : E. J2. U
Branch Box : LED402 6times Flash
Indoor Unit
Error Code
Detective details:
When open or shorted Liquid pipe Thermistor is detected.
0 5 10
168.6 129.8 100.9
40 45 50
26.3 21.2 17.8
Liquid pipe Thermistor (Unit A) (CN309 Wire:Black)
Liquid pipe Thermistor (Unit B) (CN309 Wire:Black)
Gas pipe Thermistor
Gas pipe Thermistor
Liquid pipe Thermistor (Unit C) (CN310 Wire:Black)
Gas pipe Thermistor
02-58
(Indoor unit A): LED403 Lit, LED404/ 405 Unlit
(Indoor unit B): LED403 Unlit, LED404 Lit, LED405 Unlit
(Indoor unit C): LED403/ 404 Unlit, LED405 Lit
: Operation LED 13times Flash, Timer LED 2times Flash,
Economy LED Flashing (0.1s ON / 0.1s OFF)
: J2
15 20 25
79.1 62.5 49.8
(Unit A) (CN309 Wire:Black)
(Unit B) (CN309 Wire:Black)
(Unit C) (CN310 Wire:Black)
30 35
40.0 32.4
DC