I have used them but the unit could not reverse direction in my model. I would assume it would have an internal check in the model and if you need it two way put 2 in parallel with short sections of pipe before and after each, make sure they do not conflict, work out the logic so both valves are not flowing at the same time. the short sections of pipe help the program run the numbers. anytime valves and pumps are directly connected you have the potential for problems
Hydrae