Fujitsu WATERSTAGE WS A050DD6 Series Maintenance Document page 10

Split system single phase type
Clear 2: Serial forward transfer error
Hydraulic Unit LED: Green 1 flash / Red 1 flash
Outdoor Unit LED: flash
Probable causes:
•
Misconnection.
•
External cause.
•
Interface PCB failure.
Check:
1-1. Stop the system and start it again (disconnection time 1min):
Is the error still displayed?
2. Check the connections:
- Check the connection between the hydraulic
unit and the outdoor unit.
- If there is an abnormal condition, correct it
by referring to Installation manual.
- Check the connections between the outdoor
unit main board and the active filter board.
3. Check the power supply voltage:
- Check that an AC 198 – 264 V voltage exists between terminals N and L
on the outdoor unit terminal block.
4. Check the serial signal:
- Check the voltage between terminals 2 and 3 of the outdoor terminal block. The
voltage must fluctuate between AC 70 V and AC 130 V.
- If it doesn't, replace Interface PCB.
10
YES
OK
OK
NO
1-2. Check for external causes:
- Check the system's overall isolation.
- Check for any equipment generating harmonic
waves which interfere with the communication
between the hydraulic unit and the outdoor unit.
(Neon light bulb or any electric equipment which
causes harmonic waves).
Maintenance Document 1589-3