2021 320 S overflow tube routing pic

MarkAl

I was surprised by the back pressure of filling the freshwater tank (over 1psi). I had the lower plastic off for another reason and cannot see how the freshwater tank gets to the overflow tube. I had assumed the top of the tank went directly to the overflow. Per the pics the overflow is blue and from the bottom no tube is seen but may hook into the water system above the floor somehow. Why this matters? It's imperative the overflow has minimal back pressure to avoid over pressurizing the tank and I was trying to visualize what restrictions are between the outlet and the tank.