ActronAir Evaporator Fan Blower 400mm S (PCA80S) is the factory-specified blower for the PCA80S commercial package indoor unit, providing the specific airflow volume and pressure profile designed for the PCA80S coil configuration and its commercial duct network. The 400mm impeller diameter is unique to this model -- fitting the 450mm blower from the PCA92 application will exceed the housing clearance and cause mechanical damage on startup. Isolate power at mains before replacement -- live work on fan assemblies is dangerous and must only be performed by a qualified technician.