The ornamental design for a flameless gasburnerhead, as shown and described.
FIG. 1 is a front elevational view of a flameless gas burner head showing my new design, the rear elevational view being a mirror image of the front elevational view;
FIG. 2 is a left side view thereof;
FIG. 3 is a right side view thereof;
FIG. 4 is a top plan view thereof;
FIG. 5 is a bottom plan view thereof; and,
FIG. 6 is a perspective view thereof.
The broken lines showing portions of the article form no part of the claimed design.