Richdel Valve Thumping and Air in Lines: Diaphragm or Solenoid Port Issue

Symptoms: Thumping Valve, Air in Heads, Fixed by Bleed Screw

One zone causes continuous thumping in the Richdel valve and sputtered heads. Opening/closing the bleed screw temporarily resolves it. Reoccurs on next cycle. Line is level.

Two Probable Causes

1. Worn diaphragm: Fails to seat properly, causing water hammer/thumping.
2. Clogged solenoid port: The small hole in the solenoid base is blocked, disrupting pressure balance.

Solutions

Unclog Solenoid Port

1. Turn off water.
2. Unscrew solenoid.
3. Pass a needle through the center hole to clear debris.
4. Turn water on briefly — verify steady stream through hole.
5. Turn water off, reinstall solenoid.

Replace Diaphragm

If port is clear but thumping persists, replace the diaphragm. Unscrew bonnet bolts, swap diaphragm, reassemble. See irrigationtutorials.com for detailed steps.

Why Bleed Screw Works Temporarily

Opening the bleed screw manually relieves pressure above the diaphragm, allowing it to close. But the underlying restriction (clog or wear) remains, so the fault returns on next automated cycle.