The ornamental design for a heatdeflectorplate for pellet grill, as shown and described.
FIG. 1 is a top-right front perspective view of a heat deflector plate for pellet grill, showing my new design;
FIG. 2 is a top view thereof;
FIG. 3 is a front view thereof;
FIG. 4 is a back view thereof;
FIG. 5 is a bottom view thereof;
FIG. 6 is a right-side view thereof;
FIG. 7 is a left-side view thereof; and,
FIG. 8 is a top view of the heat deflector plate for pellet grill installed in a pellet grill which is shown by dashed broken lines. The dashed broken lines showing the pellet grill is for the purpose of illustrating portions of the pellet grill and form no part of the claimed design.