Step-by-Step Guide

Understanding Auto Mode and Runtime Optimization

When programming a station to be automated by WeatherTRAK, the controller manages and optimizes your irrigation schedule by determining three key factors: how often to water, how much to water, and how best to lay that water down. This guide focuses specifically on the runtime component—the actual minutes that get generated when the controller irrigates a station.

The controller calculates runtimes based on station-specific programming that reflects the unique characteristics of each irrigation zone. By accurately matching the program settings to the real conditions in the field, you can achieve optimal irrigation performance and water savings.

Basic Settings vs. Advanced Settings

WeatherTRAK uses two categories of settings to determine irrigation schedules: basic settings and advanced settings. Understanding the difference between these is essential for making effective adjustments.

Basic settings are the landscape variables you program on day one during installation. These include information the controller cannot determine on its own, such as:

• Plant type
• Sprinkler type
• Soil type
• Slope
• Sun exposure
• Root depth
• Percent adjust

These seven basic settings represent only part of what the controller considers when generating runtime. The controller actually evaluates sixteen different variables total.

Advanced settings are the remaining nine variables that WeatherTRAK automatically fills in based on your basic settings, combined with university research and industry standards. This approach makes the system easy to program while still allowing you to edit these values if you have more specific information about your irrigation system.

The advanced settings are designed to reflect industry standards and assume a well-designed irrigation system with proper head-to-head coverage and two-sided irrigation. If your system differs from these assumptions, you may need to adjust the advanced settings to match your actual field conditions.

How Sprinkler Type Controls Runtime

When you select a sprinkler type in the basic settings, it doesn't directly control runtime. Instead, it sets two critical advanced settings into motion: sprinkler precipitation rate and sprinkler efficiency. Both of these values are instrumental in calculating runtime for your irrigation stations.

Different sprinkler types trigger different default values for these advanced settings. For example, selecting spray heads applies different defaults than selecting drip irrigation or rotor heads. Understanding how these settings work allows you to fine-tune your irrigation schedule on a per-zone basis.

Adjusting Precipitation Rate

The precipitation rate (precip rate) represents the number of inches per hour that a particular type of irrigation equipment delivers into the target area. In other words, it measures how fast water is being applied to the landscape.

When you program spray heads into WeatherTRAK, the system applies a default precipitation rate of 1.7 inches per hour. This means the controller assumes that type of sprinkler applies 1.7 inches of water to the target area in one hour's time. WeatherTRAK has default precipitation rate values for every different type of irrigation equipment commonly found in the field.

Understanding the inverse relationship: There is an inverse relationship between precipitation rate and runtime. The higher the precipitation rate number, the fewer minutes a station will run, because the controller assumes water is being applied quickly. Conversely, the lower the precipitation rate, the longer the runtime, because the controller assumes water is being applied more slowly.

As you turn the precipitation rate down, you turn the runtime up. The slower water is being applied, the more runtime is needed to deliver the correct amount of water.

When to adjust precipitation rate: The default values work well for most installations and are based on industry standards. However, every irrigation system is different. The actual precipitation rate depends on the specific spray head model and nozzle type installed on that head.

Spray heads can have precipitation rates ranging from 1.0 inches per hour to 2.5 inches per hour. The default of 1.7 falls in the middle of this range, but if your equipment is on either end of that spectrum, you may be delivering too much or not quite enough water.

How to determine the correct precipitation rate: There are several methods for obtaining more accurate precipitation rate information:

• Manufacturer's literature: Consult the technical specifications for your specific sprinkler heads and nozzles. For example, Rain Bird provides charts showing the exact precipitation rate for all their different nozzle models. Keep in mind that these values can vary based on system pressure.
• Irrigation audit: For the most precise information, conduct a professional irrigation audit. A Certified Landscape Irrigation Auditor (CLIA) can perform a cup test to determine exactly what the precipitation rate is for each station, which can then be programmed directly into WeatherTRAK.
• Observational adjustment: If you're not conducting an audit and simply want to adjust the schedule based on what you observe in the field, you can modify the precipitation rate to achieve the desired results. Just remember the inverse relationship when making changes.
  • You need to make minor adjustments to individual stations based on field observations
  • You want to quickly increase or decrease water to a zone without understanding the technical details
  • You need to comply with water district mandates for percentage-based reductions
  • You're making adjustments from a mobile device in the field
  • The adjustment needed is within the range of +25% to -50%
• You have specific technical information about your irrigation equipment that differs from the defaults
• You've conducted an irrigation audit and have precise measurements
• You have manufacturer's specifications for your specific sprinkler heads and nozzles
• Percent adjust values are exceeding +25% or going below -50%
• You're a "sprinkler nerd" who wants to optimize system performance at a technical level
• You need to compensate for poor head-to-head coverage or other design limitations