The ornamental design for a waterheatercontroller, as shown and described.
FIG. 1 is a perspective view of a water heater controller;
FIG. 2 is a front elevation view of the water heater controller of FIG. 1;
FIG. 3 is a right side view of the water heater controller of FIG. 1;
FIG. 4 is a left side view of the water heater controller of FIG. 1;
FIG. 5 is a top side view of the water heater controller of FIG. 1; and,
FIG. 6 is a bottom side view of the water heater controller of FIG. 1.
In the drawings, the claimed design is defined by the shaded surfaces; broken lines immediately adjacent shaded surfaces represent boundaries of the claim and form no part thereof; all other broken lines depict unclaimed environmental subject matter and form no part of the claim.