John-
If you change your cleaning stroke an electric will work, but, there is no comparison to using an LP heater.
For an electric heater, use hot water going into the pump (within it's recommended high range), and do fewer wet strokes on each pass before you do the dry strokes. Give it time to keep up.
If you have access to 240V, you can use one of the electric Volcano heaters from Steambrite (up to 6000 watts).