The ornamental design for a filterhousing for a water heater, as shown and described.
FIG. 1 is a perspective view showing front, top and right side of a filter housing for a water heater which has a mesh of the present design;
FIG. 2 is a perspective view showing rear, top and right side thereof;
FIG. 3 is a perspective view showing front, bottom and right side thereof;
FIG. 4 is a front view thereof;
FIG. 5 is a rear view thereof;
FIG. 6 is a top view thereof;
FIG. 7 is a bottom view thereof;
FIG. 8 is a right side view thereof;
FIG. 9 is a left side view thereof;
FIG. 10 is a cross sectional view taken along line 10-10 of FIG. 6 thereof; and,
FIG. 11 is a perspective view showing the filter housing for a water heater of FIG. 1 in a state of use as a part of environment that forms no part of the claimed design.
The broken lines shown in the drawings represent portions of the filter housing for a water heater that form no part of the claimed design. The plane including features drawn in broken line surrounding the solid line circular opening in FIG. 3 illustrates environment that forms no part of the claimed design.