On my redhawk 31f is directly behind the hot water heater under the fridge. I had to unscrew the wooden louvre/grate and the valves were there. Dont turn on the water heater until you have filled the tank, it will burn out the electrical element.
On my 22j, as mentioned above is behind louvers under fridge. There is also a plastic drain plug from outside of unit, behind plastic louvers, make sure that is tightened.