Adding Stations to a James Hardie (Irritrol) Controller: Understanding Station Limits

Why You Can't Add More Stations Than Your Controller Panel Supports

A user has a Hardie controller with part number 790201 inside the wiring compartment, but the programming label shows P/N 781001. They want to add stations beyond the 6 currently used on Program A, assuming three programs (A, B, C) × 6 stations = 18 possible stations.

Key Concept: Programs ≠ Station Capacity

• The controller panel (the faceplate with buttons/display) determines the maximum number of stations (e.g., 6, 9, or 12).
• Programs A, B, and C are just schedules that share the same physical stations. A 6-station panel can only run 6 valves total, regardless of how many programs you create.
• The terminal strip may have extra slots (up to 12), but the panel's firmware limits active stations.

Next Steps

1. Identify the exact model name/number on the controller face (e.g., "Rain Dial RD-600").
2. Visit irritrol.com (Hardie was acquired by Irritrol) for manuals and specs.
3. If the panel is a 6-station model, you cannot add a 7th station without upgrading to a 9- or 12-station panel or controller.