I discovered this today on a inspection. The home was built in 1964, with galvanize plumbing.
These plumbing pipes (pvc) went 20feet and there were 6 rows (120 feet) and returned back in to the main plumbing. It formed like a grill. I thought they may be used to compensate for possible restriction in the main in service galvanize piping. Any thoughts?? Note: water pressure was ok.