Error code
H 99 Operating indoor-unit freeze prevention
Applies to 9 models
CS-HZ25ZKE, CS-HZ35ZKE, CS-HZ25ZKE-5, CU-HZ25ZKE, CU-HZ35ZKE, CU-HZ25ZKE-5, CS-HZ25ZKE-H, CS-HZ35ZKE-H, CS-HZ25ZKE-5-H
What this means
The operating indoor unit has activated freeze prevention; a dirty unit can contribute to this code.
When to call a technician
This fault involves refrigerant, pressure, or electrical work that must be handled by a certified technician under EU F-gas rules. Do not attempt to open the refrigerant circuit, access mains wiring, or adjust pressure components yourself. Contact a qualified installer or servicer for this one.