If your model does not have a convenience center, which is does not, then your water heater bypass will be at the water heater. You could have 1 of three types of by pass systems. Single valve that uses a secondary check valve you don't see, two valves, or 3 valves.
If can cannot find ready access to the water heater from the inside, then note where the water heater is located on the outside. The inside access has to be in that same location. You most likely will need to remove a panel to get to it.
Your water pump can be located simply by turning the pump on and follow the noise.
Hope this helps:
Single valve:
2 valves:
3 valves: