I claim the ornamental design for an air intake for a water heater, as shown and described.
FIG. 1 is a perspective view of an air intake according to the present invention.
FIG. 2 is a perspective view of the air intake shown in FIG. 1.
FIG. 3 is a front view of the air intake shown in FIG. 1.
FIG. 4 is a rear view of the air intake shown in FIG. 1.
FIG. 5 is a left side view of the air intake shown in FIG. 1.
FIG. 6 is a right side view of the air intake shown in FIG. 1.
FIG. 7 is a top view of the air intake shown in FIG. 1; and,
FIG. 8 is a bottom view of the air intake shown in FIG. 1.
The present application is directed to the shape and contour of the design illustrated in the drawings. The broken line showing of the environment is for illustrative purposes only and forms no part of the claimed design.