Wilkins 720A PVB Leaks Intermittently During Cycle: Pressure Drop or Debris

Backflow Preventer Vents Water After 2–3 Days Operation

Leaks only when system runs, stops after cycle ends. 4 heads/zone, worked last year.

Causes

• Pressure drop during cycle (other water use in house, line break, too many heads).
• Plunger not seating due to debris or wear.

Checks

1. Ensure supply valve to PVB fully open.
2. Check for leaks in zone lines (pressure loss).
3. Verify PVB fed from main line tee, not downstream of house fixtures.

If Persistent

Rebuild PVB with new seat/plunger assembly.