Fujitsu WATERSTAGE 112 Maintenance Document page 37

Heat Pump, Split System, Single Service, 3 phase
Clear 14: Expansion valve thermistor error
Hydraulic Unit LED: Green 7 flashes / Red 8 flashes
Outdoor Unit LED: 6 flashes
Probable causes:
•
Misconnection.
•
Sensor failure.
•
Main PCB failure.
Check:
1. Check the sensor connection:
See if the connector has been removed
-
See if the connection is correct
-
Check for any damage on the sensor cable.
-
After solving the misconnection problem, switch the heat pump back on.
2. Remove the sensor and check its resistance value :
- Check the resistance value.
Temperature (°C)
Resistance (kΩ) 168 130 101
Temperature (°C) 60
Resistance (kΩ) 12,3 8,7
- If the thermistor is faulty, replace it.
3. Check the electronic board voltage:
- Make sure circuit diagram of outdoor unit and check terminal voltage at thermistor (DC5.0V)
- If there is no voltage, replace Main PCB.
Maintenance Document 1394-1
OK
0 5 10 15
79
70 80 90 100 120
6,3 4,6 3,4
OK
20 30 40 50
63 40 26,3 17,8
2
37