Where's the bypass for the water heater?

There are different variations of bypasses. Most I have seen have been located on the back of the water heater. Sometimes you have to remove an access panel or drawer to get to them. They are generally a series of two or three valves. There is generally a cross over pipe between the ingoing water line, and the line leaving the hot water tank. You generally close the one going to the tank, and if it has three, you close the one leaving the tank. You then open the one that diverts the cold water from the inlet pipe to the crossover to the outlet pipe, thereby bypassing the tank. Some have valves in the water bay, but I think they only install them on higher end class A.