Diagrams of water heaters exist online at About, Bradford White, HomeTips.com and Monkey Wrench Plumbing. Bradford White and Monkey Wrench Plumbing feature tankless water heater diagrams.
About's diagram is a cross-section of a tank water heater and labels water piping, gas lines, the pressure release valve and other critical components.
HomeTips.com's diagram is a side-by-side comparison of gas- and electric-powered water heaters. The diagram displays the differences between the two, including heating elements submerged in water of the electric tank and a gas supply line for the natural gas tank.
Bradford White offers PDF diagrams of gas- and electric-powered tanks and tankless heaters. Monkey Wrench Plumbing's tankless-heater diagram shows the components of the unit and the sequential steps of how the heater works.