Error code
F 99 Outdoor DC peak detection
Applies to 4 models
CS-CZ25ZKE, CS-CZ35ZKE, CU-CZ25ZKE, CU-CZ35ZKE
What this means
The outdoor unit detected an abnormal peak in direct current (DC).
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.