Irritrol RD-600 Intermittent Operation: Cold Solder Joints on Circuit Board

Symptoms: Erratic Zone Operation, Works Sometimes

The system runs zones fine some days; other days only Zone 1 works, or manual start runs for seconds then stops while controller shows running. Sun exposure isn't the issue (shaded until late afternoon).

Root Cause: Cracked Solder Joints

The Irritrol RD-600 (Hardie RD-600) is known for solder joints on the circuit board separating from contacts over time. This causes intermittent electrical connections.

Repair Options

1. DIY resoldering: Remove the board (4 screws), label all wires, power off. Resolder suspect joints.
2. Professional repair: Some suppliers (e.g., Sprinkler World of Arizona) offer board resoldering services.
3. Replace the board: Purchase a new circuit board from an irrigation supplier.

Prevention

Mount the controller in a shaded, temperature-stable location. However, the design flaw is inherent; many owners eventually upgrade to a newer Rain Dial or Rain Bird ESP controller for reliability.