If you need to replace a broken ISA 304, Rain Bird's official "Product Upgrade Guide" suggests moving to modern models like the series controllers.

Before programming, familiarize yourself with the physical layout of the ISA 304 faceplate. 1. The 24-Hour Clock Dial

Turn the dial to Custom Schedule – Days . If using Schedule C, use the arrows to toggle each day "On" or "Off".

Used to increase or decrease times, change days, and toggle settings.

You can choose specific days of the week or an interval schedule (e.g., every 2 days, every 3 days), depending on your local watering restrictions.

Each of your 4 zones can be programmed to run for a specific number of minutes. Turn the central control dial to .

Sometimes you need to water your lawn outside of the automated schedule—such as after applying fertilizer or checking for broken sprinkler heads. Manual Single Station Turn the dial to . Select the specific zone you want to water. Use the buttons to input a temporary runtime.

Place the battery into the compartment and slide the cover closed. Note: Replace this battery annually to prevent program loss during winter storms or rolling blackouts. Terminal Strip Wiring

Use the adjustment buttons to select your first desired start time (e.g., 5:00 AM).

Verify the transformer is securely plugged in. If the display is still blank, the internal fuse may need replacement.

Secure the timer to an indoor wall near a 120-volt AC outlet, ensuring it is protected from moisture and freezing temperatures.

Turn the dial to Custom Schedule – Starts . You can set up to three start times per day in 15-minute increments.

Your start times are controlled by placing trippers directly onto the 24-hour dial.

The ISA 304 offers two main ways to set a watering schedule:

Turn the knob for to the desired number of minutes (e.g., 15 minutes). Repeat this process for Stations 2, 3, and 4 .