Q: instructions for waterco 2 way valves... what does "this port cannot be closed" mean?
A: Your valve has one inlet and two outlets. When used normally the water comes in the inlet and is diverted to one outlet, the other outlet or a mix of both. If you rotate the valve so that the diverter completely covers the inlet hole, then the water has nowhere to go. If your water has nowhere to go it will very sharply raise the pressure on your filter if your pump is running and this can be dangerous. You want to make sure to rotate the lid to a potion where it does not allow the diverter inside the valve to pass over the inlet hole.