ActronAir 2020-054B Commercial Indoor PCB is the factory-fitted 2020-054b commercial indoor pcb for ActronAir split ducted systems, managing indoor fan speed control, zone output switching, and wall controller communication. A failed board causes complete loss of indoor unit operation and zone control -- fit the 100% Genuine ActronAir 2020-054B to restore factory system performance. Isolate power at mains before replacement -- live work on electrical components is dangerous and must only be performed by a qualified technician.