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Zone Won't Shut Off: Stuck Valve Diagnosis & Repair

One zone running continuously—even with system off—stops only when main water is shut off. This is a mechanically stuck valve, not a controller issue. The valve diaphragm or seat is preventing closure.

Confirm It's the Valve

Controller off/unplugged → zone still runs = valve stuck open.
Heads retract when main water shut = valve closes without pressure.
Controller not sending voltage (verified with meter) = valve mechanical failure.

Find the Stuck Valve

Turn on zones one at a time from controller.
The zone that runs when controller says "off" is the culprit.
Or: manually close flow control on each valve until flow stops.

Valve Rebuild Steps

Shut off main irrigation water.
Remove solenoid and bonnet.
Inspect diaphragm for tears, debris, mineral buildup.
Check valve seat for pitting, cracks, or debris.
Clean everything with water only.
Replace diaphragm ($10–$15) and solenoid ($15–$20) as kit.
Reassemble; test manually, then from controller.

Parts Identification

Need: Manufacturer (Toro, Rain Bird, etc.), valve size (1", 1.5"), model number. Photo the valve body. irrigationtutorials.com has detailed rebuild guides.

DIY Feasibility

Easy for a homeowner. 30 minutes per valve. Save $200+ vs. service call. If valve body is cracked, replace entire valve (cut PVC, glue new).

Irrigation: Rain Bird Drip Zone Runs Constantly: Diaphragm Replacement Needed; Fixing a Zone That Won't Shut Off: Nelson 8424 System; Rain Bird ESP-6: Cycles Twice Instead of Once - Extra Start Time; Zone Won't Shut Off? Clean the Valve Diaphragm on Your Nelson SmartZone EZ; Sprinklers Won't Shut Off? Valve Stuck Open — Not Controller; Fixing a Sprinkler Valve That Won't Shut Off: Diaphragm Replacement; Sprinkler System Won't Shut Off: Valve or Controller Fault?; Sprinkler Head Won't Shut Off – Valve Repair Guide; Fixing a Zone That Won’t Shut Off After 5 Minutes; New Valves Won't Follow Timer: Landscaper Left Flow Controls Closed

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