On one pump, you're getting 50 gpm at 1,500 rpm while only getting 16 gpm on the system pump. That's about 1/3.
The system will have more resistance due to the equipment. So, it's expected that the flow will be lower.
However, in my opinion, it's too low. The available data suggests that the suction plumbing isn't fully open. I think that there is some issue with the suction that is creating too much resistance to flow.
I would suggest a vacuum gauge get installed on the drain port of the pump to check the vacuum with various valve configurations to see if there's a problem with the lines
Maybe try both suction and returns open at the same time to see what that shows.
To do this, there's a small switch under the automated valves. It's a three position switch with middle being off.
Move the switch from one direction to the opposite direction and the valve will begin to move. When it gets half way, move the switch to the center "Off" position.
After the test, put the switches back in their original position.
The system will have more resistance due to the equipment. So, it's expected that the flow will be lower.
However, in my opinion, it's too low. The available data suggests that the suction plumbing isn't fully open. I think that there is some issue with the suction that is creating too much resistance to flow.
I would suggest a vacuum gauge get installed on the drain port of the pump to check the vacuum with various valve configurations to see if there's a problem with the lines
Maybe try both suction and returns open at the same time to see what that shows.
To do this, there's a small switch under the automated valves. It's a three position switch with middle being off.
Move the switch from one direction to the opposite direction and the valve will begin to move. When it gets half way, move the switch to the center "Off" position.
After the test, put the switches back in their original position.