ActronAir Centrifugal Fan Blower 9x9 S 600W circulates conditioned air across the indoor evaporator coil on Classic Series residential ducted systems, providing the specific static pressure profile the duct system needs to maintain rated output across all connected zones. The 600W 4-pole AC motor with 15uF run capacitor is matched precisely to the housing geometry -- substituting a different motor rating alters the system external static pressure curve and can trigger high static faults or reduced capacity at peak load. Isolate power at mains before replacement -- live work on fan assemblies is dangerous and must only be performed by a qualified technician.