NIBE F2120 alarm 228 after unsuccessful defrosting

What Does Error 228 Mean?

NIBE's F2120 installer manual associates alarm 228 with ten unsuccessful defrosting attempts. The alarm reports failed recovery across repeated cycles, not a single defective defrost part. Outdoor airflow, ice and drainage, sensors, fan, refrigerant operation, reversing process, and controls need installer evidence. Applies to: F2120 air-to-water heat pumps This definition is for the NIBE F2120 manual cited here. S2125, F2040, exhaust-air, and ground-source NIBE products have different alarm logic even when connected to a similar indoor controller or myUplink. Owner-safe checks: Record alarm history, weather, visible frost, all outdoor clearances, base drainage, runoff, and whether backup heat maintains the building. Qualified technician: Defrost history, sensor, fan, refrigeration, reversing, drainage design, installer-menu, and live electrical checks require a NIBE installer.