Sprinkler System Water Hammer: Cracked Valve Top, Loud Bang

Water Hammer Cracks Valve Bonnet: Pressure Too High, Valve Closes Too Fast

Loud BANG at cycle end, cracked automatic valve top twice. High pressure amplifies hammer.

Cause

Water at high velocity stops instantly when valve closes → pressure spike (hammer).

Fixes (Try in Order)

1. Throttle main irrigation valve (at backflow) slightly. Test. If helps → install Pressure Reducing Valve (PRV) on irrigation main. 2. Adjust valve flow control (stem on valve top) clockwise 2–3 turns to slow closure. 3. Pressure tank on irrigation line (not ideal—wrong application, fails early).

Valve Type Matters

If valves have flow control (Rain Bird PGA, Hunter ICC), use it. If not (jar-tops), PRV is best.

Reply with Valve Model

For specific alternatives, provide valve brand/model.