Is there a preferred orientation for the flapper check valves?
I assume that on vertical pipes with the water flow down is probably not a great idea. But is there much difference between putting them horizontal (lid up obviously) or vertical with water flow up?
What about with the Jandy 90 turn check valves? In a vertical plane with water turning down would would the flapper motion sideways, but seems like they could go on a vertical plane with water flowing up or horizontally with little issue.