The water pressure delivered from our provider is in the 38-42 psi range. It's gravity fed and they can't/won't increase it. I installed a Davey BT14-45T2-USA pressure booster pump to increase the water pressure and it works great with one exception: The water pressure on the side yard is down to a trickle. It was fine prior to installing the pump and it is still fine if I close the pump off from the system using the two shutoff valves and open the shutoff valve on the main line to essentially revert it back to how it was before the pump was installed.
Since the pressure on the side yard is fine when I revert things using the shutoff valves, I know it's not anything on that branch of the system like a clog, leak, etc. There is a pressure reducer valve on the side yard branch, but it's open plenty as evidenced by the pressure when the pump is closed off from the system.
With the pump on, the pressure everywhere else is now much higher, including at the hose bib shown in the photo. The main line is 1" copper. The side yard is a mix of 3/4" copper and PVC.
I don't understand why the pressure is so low on the side yard. Anyone have any ideas?