Before running the model, consider what the expected solution to this problem with only the conduction term should be.
The equation being solved is Laplace's equation, which provides the steady-state version of the heat equation. Spatially uniform values are defined on the left and right sides of the rectangular solution domain. Since the steady-state solution is being solved, there are no time-dependent effects, so the temperature field should vary linearly in the direction between the left and right boundaries. The prescribed value on the right boundary should increase with time according of the function.