Fisher FSKIF-121AE2-EU Service Manual page 141

2.4.3 For the unit with TWINS function (For the super-slim cassette & duct)
2.4.3.1 Communication
E8
2.4.3.2 Other malfunction between master unit and indoor unit
One indoor unit displays "E9", which means another indoor unit is faulty. Check another indoor unit's error
code and then follow the appropriate solutions to solve the malfunction.
Electrical Control System
between master unit and indoor unit
malfunction
Troubleshooting
137