Did you find the back of the water heater? You should find 3 valves on the lines going to the heater. One one the inlet, one on the outlet, and a line hooked between the two lines with a valve in it. It will be on the back of the heater,,, maybe under the seat of where ever the heater is located. Best I can say is find the front of the water heater outside and then determine what is covering the back side. That is where you will find the bypass valves.