All Zones Run Simultaneously: Controller Fused or Solenoid Stuck

Spring startup: all zones run at once. Manual valve operation no diff on zones 1-2, slight on others. 24V at solenoids. Bleed, disassembly, flush, mainline trench—no leaks found. Zones won't shut off.

First Check: Unplug Controller

Matt: "This may sound simple, but have you unplugged the controller? I've had a few controllers get fused so they are applying power to the valves all the time."

Second Check: Solenoid Plunger Movement

"Remove a solenoid and make sure the plunger is moving. When you have it in your hand, have someone turn the zone on and watch the center of the solenoid. You should see or hear the plunger snap in and then out when the power is turned off."

Need Model Info

Controller and valve models would help diagnose further. But fused controller output (relay/triac welded shut) is a classic "all zones on" failure mode.