The ornamental design for a drain pan for heatexchanger, as shown and described.
FIG. 1 is a front perspective view of the front, left, and bottom sides of a drain pan for heat exchanger showing of our new design;
FIG. 2 is a rear perspective view of the rear, right, and top sides of thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a rear view thereof;
FIG. 5 is a left side view thereof;
FIG. 6 is a right side view thereof;
FIG. 7 is a top plan view thereof;
FIG. 8 is a bottom plan view thereof; and,
FIG. 9 is a reference view of usage.
The broken lines shown represent unclaimed subject matter of the drain pan for heat exchanger and form no part of the claimed design. The dash-dot lines represent the boundary between the claimed design and unclaimed design.