Error code
H 21 Indoor float-switch fault
Applies to 6 models
CS-NZ25YKE, CS-NZ35YKE, CS-NZ50YKE, CU-NZ25YKE, CU-NZ35YKE, CU-NZ50YKE
What this means
The indoor float switch operation is abnormal.
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.