Toro Zone 4 Runs Constantly: Manual Valve Operation Guide

When zone 4 runs whenever water is on—controller off or not—the valve is stuck open. Here's how to manually operate Toro valves to diagnose.

Toro Valve Manual Operation

• Center top screw (bleed screw): Turn ½ turn CCW → water sprays from top, valve opens.
• Solenoid bleed: Unscrew solenoid (black cylinder) ½ turn → valve opens.
• Plastic lever near solenoid base: Flip up → pushes plunger, opens valve.

Diagnose Zone 4

1. Shut off water.
2. Remove solenoid from zone 4 valve. Check plunger: moves freely? Spring returns?
3. Reinstall solenoid, turn water on. Zone 4 still run? → Diaphragm torn or debris in seat.
4. Disassemble valve, replace diaphragm.

Identify Which Valve Is Which

Turn on one zone at controller, watch which valve box activates. Or manually bleed each valve until the corresponding heads pop up. Label them.

Zone 4 valve is mechanically stuck—controller isn't the issue.