Error code
55 Dust box or air filter not fitted
How it shows on the unit OPERATION 5 blinks, TIMER 5 blinks (each 0.5 s on/0.5 s off) while ECONOMY flashes rapidly (0.1 s on/0.1 s off)
Applies to 2 models
ASYG09KXCA, ASYG12KXCA
What this means
The installation manual lists this pattern as a filter-set fault; the owner manual explains it means the dust box or air filter is not fitted securely.
What you can check yourself
- Switch off the power, then refit the dust box and air filter so they sit level and secure and the intake grille is fully closed.
- If the pattern returns after refitting, contact an authorized technician.
Still not resolved? Contact a qualified installer or servicer.
See the Fujitsu manual (hosted by an authorized distributor)Hosted by an authorized distributor rather than by the manufacturer. We link to manuals, we never host them.
Using Claude Code or Meta Muse? Connect HeatPump AI and ask it about 55.