Irrigation Valve Wiring Methods: Conventional vs. Two-Wire Decoder

How many ways to wire valves from valves to controller?

1. Conventional (Standard) Wiring

• One common wire (usually white) connects to one terminal on every valve.
• Each valve gets a dedicated hot wire to its station terminal on the controller.
• Multiple valves can share a hot wire to run simultaneously (same zone).

2. Two-Wire Decoder System (Modern)

• Only two wires run the entire system.
• Each valve has a decoder with a unique address.
• Controller "calls" the decoder to activate its valve.
• Unforgiving of wiring errors—professional installation recommended.

Conventional is universal for residential/small commercial. Two-wire is for large systems (50+ zones) where wire savings justify decoder cost.