FIG. 1 shows a front view of a fan unit for ionizer showing my new design;

FIG. 2 shows a rear view thereof;

FIG. 3 shows a right side view thereof;

FIG. 4 shows a left side view thereof;

FIG. 5 shows a top view thereof;

FIG. 6 shows a bottom view thereof;

FIG. 7 shows a top, front and right side perspective view thereof; and,

FIG. 8 shows a bottom, rear and left side perspective view thereof.

The portions of the design shown in broken lines in FIGS. 1, 2, 7 and 8 are for the purpose of illustrating the environment only and form no part of the claimed design.