Fujitsu WATERSTAGE 112 Maintenance Document page 45

Heat Pump, Split System, Single Service, 3 phase
Clear 26: Low pressure abnormal
Hydraulic Unit LED: Green 10 flashes / Red 5 flashes
Outdoor Unit LED: 20 flashes
Probable causes:
•
Connector connection failure.
•
Pressure Sensor failure.
•
Main PCB failure.
•
Gas leak, less.
Check:
1. Check connection of the Pressure Sensor:
- Check if the terminal connection is loose.
- Check if connector is removed.
- Check if connector is erroneous connection.
- Check if cable is open.
Upon correcting the removed connector or mis-wiring, reset the power.
2. Check output voltage of Main PCB :
Check voltage of Main PCB (Measure at Main PCB side connector)
1 pin(Red) - 3 pin(Black) DC5V +/- 5%
If the voltage is not correct, replace Main PCB.
3. Check if gas leak or less gas
Measure Gas pressure, if there is a leak, correct it.
If recharging refrigerant, make sure to perform vacuuming and
recharge the specified amount.
4. Replace Pressure Sensor
If Check Point 1 ~ 3 do not improve the symptom, replace Pressure
Sensor.
Maintenance Document 1394-1
OK
OK
OK
45