The ornamental design for a heatexchangerbaseplate, as shown and described.
FIG. 1 is a front perspective view of a heat exchanger base plate;
FIG. 2 is a top perspective view of a heat exchanger base plate;
FIG. 3 is a back perspective view of a heat exchanger base plate;
FIG. 4 is a bottom perspective view of a heat exchanger base plate;
FIG. 5 is a front view of a heat exchanger base plate;
FIG. 6 is a back view of a heat exchanger base plate; and,
FIG. 7 is a top view of a heat exchanger base plate.
In the drawings, the broken lines depict environmental subject matter only and form no part of the claimed design. The dot and dashed boundary lines indicate a boundary between the claimed and unclaimed portions of the design.