The attached photo shows the flow diagram for the APRO5500 membrane. You can also find that photo at the bottom of this post.
The new shut-off valve has a different design than the original.
The previous design had the in-and-out on the right side, with the plumbing running horizontally. The new design will also feature the in-and-out on the right side, but with the flow rate running vertically.
The inlet tube comes from the right filter and the outlet tube goes to the feed of the membrane. Replace each tube one by one, or mark the tube and new valve by #1, #2, #3, #4.
If you have any questions or comments, please let us know!