Backflow Prevention for Irrigation Systems

In this first lesson, I will give you a quick introduction to backflow prevention and a real-world example of the hazard that sprinkler systems present to the potable water supply. Then I'll drop a few anecdotes of backflow gone wrong and the consequences.

Learn the definitions of terms used in the backflow prevention arena. We'll cover important concepts like Backpressure and Backsiphonage.

This lesson briefly touches on regulations that cover Backflow Prevention at the national and state level. I also give an explanation of why this lesson doesn't cover the testing of backflow preventers.

We'll take a tour through the 3 types of backflow preventers; Methods, Devices, and Assemblies. You'll get to see all of the different types of backflow preventers that are common to the irrigation industry.

* Skill Builder Exercise in this lesson

We cover both kinds of Residential Dual Checks, the non-rebuildable units and also the rebuildable ones. We break down a Zurn Wilkins "Model 700 Dual Check Valve Backflow Preventer." You'll also get some practical installation advice.

The Anti-Siphon Valve is a category of backflow preventer that intersects with solenoid valves. Every manufacturer has a version of this valve, and it's quite popular. I'll walk you through some illustrations that will help you understand this type of backflow prevention in context of the supply types. We'll also go through some diagrams of how these valves actually work, which will also help you understand the atmospheric vacuum breaker.

* Skill Builder Exercise in this lesson

We'll have a thorough conversation about the Pressure Vacuum Breaker and the use cases for them. Then we'll break down a Zurn Wilkins "Model 710 Pressure Vacuum Breaker."

* Skill Builder Exercise in this lesson

The Double Check Valve Assembly is one of the most commonly used backflow preventers used in the USA for irrigation systems. I'll explain all the testcocks, check valves, and shut-offs so you have an orientation of the unit. Follow along as we take apart a check valve on an old Wilkins 950XL and put it back together.

The Reduced Pressure Principal Assembly is a backflow preventer that you're not likely to see on irrigation systems for residential and light commercial use. If you get licensed by your state (in the USA) or regulatory jurisdiction, you'll have to understand these units intimately. I cover these in this course so you'll recognize them and also recognize the High Hazard that they're probably protecting.

This lesson is about troubleshooting the backflow preventer in context of the irrigation system and it's potential issues. Since the backflow preventer is the beginning of the system, it's important to understand the testcocks and how to use them to check the device for issues.

* This doesn't cover anything related to testing and the many troubleshooting and repair steps that certified testers will encounter. Your home state certification school will teach you all about testing and those repairs.