Ok so judging by your picture (correct me if im wrong) but your biggest mistake was not using check valves on each line before they meet. Always use a check valve or else have fun cranking one machine and then cranking the second one and have it kick back and start swearing up and down how you hate this business lol
Also why is one end looping back into the another end??? Its supposed to be “A, B, C” . Meaning a TEE has three ins/outs. 2 are supposed to be ins and one out. Almost looks like you are trying to output one machines gpm into the other one… Not how it works… i have a post here on how its supposed to look like.
