Troubleshooting Irrigation Zone Valves

Even the most experienced irrigation contractors can encounter challenges with irrigation zone valves during field operations. These issues are a normal part of the job and not a reflection of your skills or expertise. It’s the ability to effectively troubleshoot that’s most important; that’s what makes you a pro.

Each type of irrigation valve has its own specific role, advantages and common issues. Understanding these can improve your efficiency and effectiveness in the field. At SiteOne® Landscape Supply, we’re here to equip you with the knowledge, tools and support you need to tackle valve problems head-on, so you can maintain project timelines and client satisfaction.

Types of Irrigation Valves
Irrigation systems rely on a variety of valves, each designed to fulfill a specific function in managing water flow. Irrigation valves not only differ in design but also in their applications.

• Gate Valves: These valves are primarily used for on/off control and offer reliability through a simple mechanism. They are typically seen in larger systems, such as those used on golf courses and sports fields, to isolate and manage water flow.
   
• Globe Valves: Globe valves are durable and used to throttle flow, making them suitable for applications that require precise water control, such as household irrigation systems. Their ability to adjust flow finely is valued in systems that need modulation.
   
• Butterfly Valves: Designed for larger pipes, butterfly valves provide quick shut-off and a low-pressure drop. Their compact design is beneficial in settings where space efficiency and ease of use are priorities. These valves are often used on pump stations and pumps to manage flow and isolation capabilities.
   
• Plug Valves: Plug valves manage flow with a cylindrical or conically tapered plug that rotates within the valve body. They are chosen for their ability to maintain a consistent flow rate and pressure without causing turbulence. They’re not often used in irrigation systems, but rather, in waste treatment plants or situations with significant debris in the water.
   
• Ball Valves: Ball valves use a rotating sphere with a hole through its center to provide quick and reliable shut-off with minimal pressure loss. Their simplicity and durability make them ideal for frequent operation in irrigation systems to isolate certain sections.
   
• Diaphragm Valves: Diaphragm valves regulate flow using a flexible diaphragm that moves up and down, isolating the valve components from the fluid stream. They are often used where contamination prevention and purity are crucial, such as in systems that involve fertilizers.
   
• Solenoid Valves: These electrically controlled valves play a crucial role in modern irrigation systems by enabling automatic watering schedules. They can be integrated into the mechanical valves listed above for efficient water management, particularly in large-scale or complex irrigation setups where precise control and timing are essential.

Common Problems and Solutions
No irrigation system is immune to occasional issues. Here are some common problems with irrigation valves and their initial troubleshooting steps:
 

Valve Won't Open
One of the most frequent issues in irrigation systems is a valve that fails to open. This is often due to an issue with the irrigation controller. Physical blockages caused by dirt, rocks or other debris can also prevent a valve from opening. To address this, first check and secure all electrical connections to the solenoid and ensure that it is receiving adequate power. If the electrical system and the irrigation controller are functioning correctly, examine the valve diaphragm for any debris that may be obstructing movement and clear it away to restore functionality.
 

Valve Leaks or Won't Close Completely
A valve that leaks or won’t close completely is typically caused by debris or a worn-out diaphragm. Check to see if there is a manual bleed screw and make sure it has not been turned to the open position. You will see running water from the bleed screw if it has been left in the open position.

Debris can interfere with the valve's ability to form a tight seal, while a degraded diaphragm may lose its flexibility and effectiveness. First, determine which type of valve you are working on. To resolve this issue in a diaphragm valve, start by cleaning the valve seat and diaphragm thoroughly to remove any particles or buildup. If cleaning does not resolve the problem, assess the condition of the diaphragm and replace it if it is damaged or excessively worn. 
 

Low Water Pressure
Experiencing low water pressure in an irrigation system can be due to partially closed valves (depending on the type) or leaks within the system. Begin troubleshooting by ensuring that all valves are fully open and are not partially restricting water flow. Check the pressure at the source or supply for the system.

Next, inspect the entire system for leaks, which can diminish pressure and efficiency. Repair any detected leaks promptly. If the issue persists even after these steps, some components of the system might be failing and require replacement to restore proper water pressure.
 

Erratic or Intermittent Operation
Irrigation systems that operate erratically often have underlying issues with the controller settings or wiring. Incorrect controller settings can lead to irregular operation patterns, while damaged or loose wiring can disrupt the electrical signals needed for smooth operation. To correct these problems, first ensure that all controller settings are correctly configured according to the system's requirements. Then, inspect the wiring for any signs of damage or loose connections and make necessary repairs or adjustments to ensure stable and consistent operation.
 

Stuck Valves
A valve may become stuck in either the open or closed position, often due to sediment build-up, rust or wear and tear of mechanical components. This can prevent the valve from functioning properly and disrupt the overall water flow control in the system. To resolve this, first attempt to manually operate the valve to determine if it can be moved. If the valve remains stuck, disassemble the valve carefully to inspect and clean its internal components. In cases where the valve is damaged or severely worn, replacing it may be the most effective solution.
 

Solenoid Failure
Solenoids are critical components that control the opening and closing of valves via electrical signals. A failure can occur due to solenoid burnout, corrosion, or damage from voltage fluctuations such as a lightning strike. To troubleshoot, use a multimeter to measure the solenoid's resistance. Typically, the expected resistance range for solenoids in irrigation systems should be between 20 to 60 ohms, but always refer to the manufacturer’s specifications for precise values applicable to your specific model. If the resistance is too high or too low, the solenoid will need to be replaced. Additionally, ensure that the solenoid is not experiencing voltage drops or surges, which could be indicative of electrical issues elsewhere in the system.
 

Electrical Faults
Faults in the electrical system, such as short circuits, disconnected wires or water-damaged components, can cause valves not to actuate properly. To diagnose these problems, conduct a thorough inspection of all electrical connections and components using a multimeter to check for continuity and proper voltage levels. Repair or replace any faulty wiring or components found during the inspection to ensure the electrical system is stable and functional.
 

Pressure Regulator Failures
Pressure regulators maintain a constant pressure in an irrigation system to ensure efficient water use and prevent damage to the system. Failure can result from wear, incorrect settings or blockages. Check the regulator settings to ensure they are correct for your system’s requirements. If the settings are correct but the problem persists, inspect the regulator for blockages or signs of wear and replace it if necessary.

You’re Not Alone
SiteOne’s local branch associates are always ready to provide expert advice, answer questions and help troubleshoot any issues you might encounter. You can also browse our online irrigation resource center to proactively enhance your skills and understanding. When you need it, our comprehensive inventory is available around the clock here on our website and through the SiteOne mobile app. We’re here to support your success in every way, every day.