Low Pressure on Third Valve – Increase Pipe Size or Reduce Nozzle Flow

3-valve manifold, 3/4" PVC. Two zones work; third (10 Toro pop-ups) weak. 50-60 ft to first head, split run.

Solution

• Friction loss in long 3/4" line.
• Increase to 1" pipe, or
• Install lower-flow nozzles (reduce GPM, increase pressure).

Lube won't help; leak would show no pressure at all.