Fujitsu Comfort Series Service Manual page 32

Troubleshooting 11
OUTDOOR UNIT Error Method:
Outdoor unit Heat Exchanger
Thermistor Error
Detective Actuators:
Heat exchanger Outlet / Middle temperature
thermistor
Forecast of Cause :
1. Connector connection failure, open
2. Thermistor failure
3. Main PCB failure
Check Point 1 : Check the connector connection and cable open
Connector connection state check
Cable open check
OK
Check Point 2 : Check the thermistor
Thermistor characteristics check
(Disconnect the thermistor from the PCB and check.)
* For the thermistor characteristics, refer to the "Service Parts Information 5".
OK
Check Point 3 : Check voltage of Main PCB (DC5.0V)
Main PCB P15:1-2 voltage value =5V
Main PCB P1 :1-2 voltage value =5V
Remove the thermistor from Main PCB, check the voltage.
1 2 3 4
1 2 3 4
P15
If the voltage does not appear, replace Main PCB,
and execute the check operation again.
Indicate or Display:
Hydraulic unit :
Green Red
7 3
n : n times blinking
Detective details:
Heat exchanger outlet temperature thermistor short or open detected
Heat exchanger middle temperature thermistor short or open detected
1 2 3
1 2 3
P1
03-13
Outdoor unit :
Mode Error L1 L2
2 7 3
: Light OFF : Light ON
DC
L3 L4 L5 L6
n : n times blinking