Hitachi FSXN Series Service Manual page 242

8 Troubleshooting
C2
Alarm code
• The unit no., alarm code ("35") and the unit code are alternately indicated in the temperature setting section of the indoor
unit connected to the CH unit.
• LED (LED4, 5, 6) in PCB(1) of the CH unit flashes.
* < Heat recovery system (3 pipes) >
This alarm is indicated when nine or more indoor units are connected to the CH unit.
Are 9 or more indoor units
connected to CH unit?
No
• Alarm code "C2" will be indicated when the units are connected as follows.
Outdoor Unit
(Ref. Cycle Group: 1)
CH Unit
Indoor Unit 1 Indoor Unit 2
(Ref. Cycle Group: 1) (Ref. Cycle Group: 1)
236
SMGB0065 rev. 1 - 12/2010
Incorrect setting of the indoor unit connection number (CH unit).
PCB1: Control PCB in Outdoor Unit
PCB(1): CH Unit PCB
Yes
Indoor Unit 3
(Ref. Cycle Group: 1)
Correctly connect the wiring
and reset the power supply.
Failure of PCB(1) in CH unit
Indoor Unit 9
(Ref. Cycle Group: 1) 1)