Fujitsu Waterstage WS G140DC6 Series Maintenance Document page 15

Split system (Single phase and 3-phase type)
Clear 9: Outdoor temperature thermistor error
Hydraulic Unit LED: Green 7 flashes / Red 4 flashes
Outdoor Unit LED: 7 flashes
Probable causes:

Misconnection.

Sensor failure.

Main PCB failure.
Check:
1. Check the sensor connection :
See if the connector has been disconnected.
-
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) 115 62,3 46,6 35,2 26,9 20,7 16,1 12,6 7,97 5,18 3,45 2,36 1,65
- 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)
THERMISTOR
(COMPRESSOR)
THERMISTOR
(OUTDOOR)
THERMISTOR
(PIPE)
THERMISTOR
(DISCHARGE)
THERMISTOR
(HEAT SINK)
THERMISTOR
(PIPE MID)
THERMISTOR
(EXPANSION)
- If there is no voltage, replace Main PCB.
Maintenance Document 1544-1
OK
-20 -10 -5 0
OK
5 10 15 20 30 40 50 60 70
15