Rain Dial Zone Won't Shut Off After Seasonal Startup

After winter shutdown, zone 1 on a Rain Dial system runs but won't shut off when advancing to other zones. Manual zone checks worked initially.

Common Cause: Debris in Valve

Extended shutdown allows scale, rust, or sediment to settle. When restarted, a particle can lodge in the valve seat or diaphragm, holding it open.

Repair Steps

1. Locate the zone 1 valve box.
2. Remove the solenoid and clean the plunger and port.
3. If needed, remove the valve bonnet, inspect the diaphragm for tears, and flush all ports.
4. Reassemble; often the act of disassembly dislodges the contaminant.

This is routine maintenance for systems winterized for months. Replacing the diaphragm while the valve is open is inexpensive insurance.