Error code
H12 Indoor unit capacity mismatch
Applies to 22 models
CS-TZ20WKEW, CS-TZ25WKEW, CS-TZ35WKEW, CS-TZ42WKEW, CS-TZ50WKEW, CS-TZ60WKEW, CS-TZ71WKEW, CS-RZ20WKEW, CS-RZ25WKEW, CS-RZ35WKEW, CS-RZ50WKEW, CU-TZ20WKE, CU-TZ25WKE, CU-TZ35WKE, CU-TZ42WKE, CU-TZ50WKE, CU-TZ60WKE, CU-TZ71WKE, CU-RZ20WKE, CU-RZ25WKE, CU-RZ35WKE, CU-RZ50WKE
What this means
Connected indoor-unit capacity, quantity, or combination is outside the permitted range.
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.