All Irritrol Zones Stuck On: Valve Bleed Screw, Solenoid, or Diaphragm

All three zones run with controller off—valves stuck open. Three causes, in order of likelihood.

1. Bleed Screw Open

Black plastic screw on valve top. If water leaks from it, tighten clockwise. Valve closes.

2. Solenoid Plunger Stuck

Unscrew solenoid, check plunger moves freely. Clean, lubricate lightly with silicone grease. Reinstall.

3. Diaphragm Torn

Shut off water, remove bonnet (8 screws), inspect diaphragm. Tears = replace. Clean seat.

Process

1. Check bleed screws first (30 sec each).
2. If all closed, test solenoids.
3. If solenoids OK, replace diaphragms.

One of these three fixes it. Start simple.