Fujitsu Waterstage WS G140DC6 Series Maintenance Document page 13

Split system (Single phase and 3-phase type)
Clear 7: Discharge thermistor error
Hydraulic Unit LED: Green 7 flashes / Red 1 flash
Outdoor Unit LED: 2 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) 168 130 101
Temperature (°C)
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)
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
0 5 10 15
79
60 70 80 90
6,3 4,6
OK
20 30 40 50
63 40 26,3 17,8
100 120
3,4 2
13