Low Pressure on One Sprinkler Zone: Valve Adjustment and Cleaning

Diagnosing Single-Zone Pressure Problems

One zone with 7 sprinkler heads shows only one head operating normally. The other six produce insufficient spray coverage, indicating a pressure/flow issue isolated to that zone.

Step-by-Step Troubleshooting

1. Adjust the zone valve flow control: Open fully counterclockwise, then close fully clockwise counting turns. Reopen to half the counted turns.
2. If adjustment fails: Disassemble the valve and clean internal components (diaphragm, solenoid ports, valve seat).
3. Check electrical connections: Verify solid wire connections at the valve solenoid and controller terminal.
4. Consider valve replacement: If cleaning doesn't restore flow, replace the valve—often simpler and more reliable than rebuilding older units.

Pro Tip

Always turn off the main water supply before disassembling valves. Take photos during disassembly to ensure correct reassembly.