Hardie RD-1200 Valves Not Shutting Off: Solenoid, Controller, or Diaphragm Issues

Some Lines Stay Open Continuously on Hardie RD-1200

When sprinkler zones fail to close, four root causes exist:

1. Faulty solenoids on the affected valves—replace them.
2. Controller sending constant 24 VAC to those terminals—replace controller.
3. Dirt/debris inside the valve preventing sealing—disassemble and clean.
4. Damaged diaphragms—replace diaphragm assemblies.

Detailed valve cleaning/rebuild guides at irrigationtutorials.com.