Ionizing Wire length
The spring lever for the ionizing wires was redesign in May 2005. The ionizer frame has remained compatible with previous versions, but the spring levers have changed.
The redesign of the spring lever changed the ionizing wire length. The series one spring levers use the wire Aprilaire 4315. The series one spring levers are shown below.
The photo below shows the series two ionizer frame. The stainless steel spring levers for the ionizing wires are different than the above. Ionizer frame's with these spring levers use ionizer wire Aprilaire 4602.