Irrigation solenoid valves are a key component of any irrigation system. The solenoid valve is responsible for controlling how much water is released at any given time or on your command. But what should you do if one of them doesn’t work properly? How do you find the cause of the problem?

The most common issues with solenoid valves are not opening or closing properly and overheating. These issues can sometimes be solved by cleaning out debris, but are sometimes the result of an electrical or water pressure issue, which may require professional assistance.

This guide serves as a toolbox for those who are currently dealing with problems with their irrigation valves, or simply want to know how to solve these issues in advance, should they happen. Continue reading to learn more.

What Is An Irrigation Solenoid Valve?

An irrigation solenoid valve is a valve that is controlled through the use of electricity for the regulation of water flow. The voltage that is applied over the coil causes the valve to open, allowing liquid to flow through.

Irrigation solenoid valves are also referred to as electromagnetic valves, electric or electro valves, and water valves. They consist of an electromagnetically inductive coil, shading ring, spring, a plunger, the seal, and the valve body itself.

A valve can either be normally open (NO), which means it is open at rest, or normally closed (NC), which means it is closed at rest.

Irrigation solenoid valves are used in a wide variety of applications — from low to high pressures and from small to large liquid flow rates. As such, these valves come in different circuit functions, types, and working principles. These valves are classified into one of the circuit functions:

The 2-way solenoid valve has two ports as well as an inlet and an outlet. The direction of the liquid’s flow is important for the proper operation, which is why these valves usually have an arrow indicating the flow. These 2 way valves are used in closing or opening an orifice.

The 3-way solenoid valve on the other hand can be used in two positions, which allows it to switch between two different circuits. These valves are used to open, close, distribute, or mix liquids, such as in fertigation systems.
These solenoid valves are further classified into different types, the normally closed (NC) solenoid valve, the normally open (NO) solenoid valve, or the Bi-stable solenoid valve.

Normally Closed Solenoid Valve – A normally closed solenoid valve is a valve that is closed in its unpowered state.

Normally Open Solenoid Valve – A normally open solenoid valve is the inverse of a NC solenoid valve, and allows water to flow when unpowered.

This type of valve is commonly seen where water flows the majority of thetime and only closes when needed. Bi-Stable Solenoid Valve – This type of valve has no defined unpowered state, and can be toggled between open and closed states. This system is far more versatile and uses magnets, unlike NO and NC valves, which use springs.

What Causes Solenoid Valve Failure?

Solenoid valve failures are caused by either the failure of the electromagnetically inductive coil, or the failure of the valve itself. Some of the common causes of solenoid valve failure include
Incorrect Voltage – An excessive voltage running through your solenoid valve can easily burn and short it out. A burnt out coil cannot be repaired and you’ll need a replacement solenoid coil, so it’s essential to make sure that when you are installing a solenoid valve, the voltage allowance matches the voltage output of your irrigation system.

By installing electrical surge protection, you have an added safety against spikes in voltage that can be caused by things like lightning and static electricity.

Liquid Contact – As this is an electrical device, direct contact with water or other liquids can completely short out the coil, requiring a new coil instantly. This can be mitigated by using a suitable DIN connector to protect vulnerable electrical points. Some solenoid valves come with basic o-rings to help create watertight seals, however, better protection may be required for outdoor or damp environments.

Your irrigation contractor or irrigation supply store can advise you on the best way to keep your solenoid valves dry and free from moisture, including a high quality irrigation valve box.

Sediment Damage – Although uncommon, small amounts of sediment can get into your solenoid valve and cause significant issues. Apart from damage to the system itself, sediment will prevent movement within the valve, causing the system to overheat, damaging the components within the valve. Installing an irrigation filter upstream will help prevent sediment reaching your valves, as will installing your valve vertically.

Excess Water Pressure – If the water pressure running through your irrigation system exceeds the pressure that your solenoid valve can handle, it will lead to the solenoid valve being ruptured, and in some cases, a larger section of your irrigation system needing to be replaced. Be sure to check the pressure tolerances of all parts of your irrigation system before installing them.

Temperature Changes – A significant change in temperature can also be a cause for damaged solenoid valves. Solenoid valves are only rated to handle a set temperature, and exceedingly hot or cold weather can wear these valves to the point where they may need replacing.