Heater

FIG. 1 is a front, left, top perspective view of a heater, showing my new design; FIG. 2 is a rear, right, bottom elevational view of the reduced scale thereof; FIG. 3 is a front, right, bottom elevational view of the reduced scale thereof; FIG. 4 is a front elevational view thereof; FIG. 5 is a rear elevational view thereof; FIG. 6 is a left side view thereof; FIG. 7 is a right side view thereof; FIG. 8 is a top plan view thereof; FIG. 9 is a bottom plan view thereof; FIG. 10 is an enlarged view of detail 10 in FIG. 1 ; FIG. 11 is an enlarged view of detail 11 in FIG. 1 ; FIG. 12 is an enlarged view of detail 12 in FIG. 1 ; FIG. 13 is an enlarged view of detail 13 in FIG. 3 ; FIG. 14 is an enlarged view of detail 14 in FIG. 3 ; FIG. 15 is an enlarged view of detail 15 in FIG. 3 ; FIG. 16 is an enlarged view of detail 16 in FIG. 4 ; FIG. 17 is an enlarged view of detail 17 in FIG. 4 ; FIG. 18 is an enlarged view of detail 18 in FIG. 6 ; FIG. 19 is an enlarged view of detail 19 in FIG. 6 ; and, FIG. 20 is an enlarged view of detail 20 in FIG. 8 . The dashed broken lines in the figures are for the purposes of illustrating portions of the Heater and form no part of the claimed design. The short-short-long dashed broken lines immediately adjacent to the claimed areas in the views represent the boundaries of the design and form no part of the claimed design. The dash-dot-dash broken lines are for notating enlarged views and form no part of the claimed design.