Everything You Need to Know About Fuel Water Separators (and Why Maintenance is Critical)

Fuel water separators are important to any fuel system, whether it’s diesel or marine. They play a crucial role in preventing damage and corrosion to vital components and help to preserve the service life and engine quality. But their purpose goes beyond keeping the fuel clean; fuel water separators also increase the reliability of the vessel. These devices are essential to certain kinds of machinery and their maintenance is critical.

In this blog, we will cover everything you need to know about fuel water separators including some basics on what they are, how they work, and some things to consider when purchasing one. 

What is a Fuel Water Separator?

In the simplest of terms, a fuel water separator is a small filtering device that removes water from fuel before it reaches the most sensitive parts of an engine. This might be for a diesel engine or for a marine engine, or some other kind of industrial machinery. A fuel water separator is critical to ensuring that clean fuel is delivered to an engine. This is because water and other contaminants can have a direct impact on the service life and performance of engines.

There are two common types of fuel water separators: diesel fuel water separators and marine fuel water separators.

Diesel fuel water separators are made of aluminum and available in several different sizes, depending on your needs. Water is collected in a trap and drained out of the engine at a later time. Marine fuel water separators are often made of plastic or aluminum. They are mostly used in marine vessels to help filter out water that may seep into the motor. In a marine vessel, if too much water enters the motor it could potentially lead to an explosion.

As mentioned earlier, a fuel water separator is a type of filter that prevents contaminated fuel, debris, and water from reaching an engine. This happens in six steps:

1. Condensation of water in the fuel tanks. Diesel fuel tanks are mostly subjected to water condensation compared to gasoline because it has no vapor pressure that can displace air. When the fuel tank is warm, the air inside expands and is forced out. The moment the tank starts to cool down, humid air is then drawn back into the tank, making water that condenses out on the tank’s walls.
2. Removal of water from the fuel. When fuel is contaminated with water, it’s pumped from the fuel tank. The water leaves the tank as droplets that are relatively easy to remove from fuel using a fuel water separator. If the water is not removed quickly before passing through the pump, the fuel/water mixture will form an emulsion and make it difficult to separate.
3. Installation of the water separator. Fuel water separators are designed to fit as a series of installations inside a system. Fitting a separator into a system requires an OEM fuel filter. Fuel must pass through the OEM fuel filter and the fuel water separator before reaching fuel delivery components, such as injectors. This is to ensure that only clean fuel enters the engine.
4. Flow of Fuel. After installing the fuel water separator, it becomes the first point of contact for all the fuel from the vehicle’s fuel tank. This is the point where the process of filtering starts before accessing the engine. Fuel flows through the first opening and then through the fuel water separator to the center of the separator unit up to the water trap. At this point, any denser contaminants than fuel, such as water, will fall to the bottom of the trap.
5. Separation of water and contaminants. At this stage, all of the water is filtered through the separator unit. Any solid particles left in the waterless fuel are filtered as well.
6. Draining water from the separator. After separating water from fuel, the water is drained from the fuel water separator through a valve. Allow the filter drain water to flow until clean fuel flows out and then close the valve.

Why Do I Need a Fuel Water Separator?

Water can cause a number of problems for your machinery’s engine such as rust, grime, bacteria, fungus, and ultimately destroying the functionality of your engine. Separating water and other contaminants from your fuel, it ensures that your machinery’s engine runs smoothly and efficiently. It will also help to prolong the life of the engine by preventing corrosion and other damage caused by water and debris.

When choosing a fuel water separator, be sure to select one that is compatible with your fuel system. And be sure to regularly check and clean your separator to ensure it works properly. There are several problems that come with having water in your fuel, ranging from irreversible damage to your machinery’s engine, developing rust that can lead to machine failure, damage to other pieces of equipment near the fuel tank/engine, and more. 

Choosing the Right Fuel Water Separator

If you’re in need of a fuel water separator, there are a few factors to take into consideration, including the filter’s filtrating rating, the kind of collection bowl it comes with, as well as your engine’s fuel consumption rate. There are several fuel water separators on the market, but to find the most effective one you need to be selective with each model and find a device that suits your specific needs. A good rule of thumb is that the bigger your machinery’s engine, the larger your fuel water separator needs.

After going through this article on how fuel water filters work, you now understand the process and why it is crucial to not only filter your fuel before reaching the engine but maintain your fuel water separator. 

At ACI Controls, you can find the right fuel water separator for your specific needs. ACI’s team of experts can help you find the right fuel water separator for your application from our extensive inventory or design a custom solution to meet your specific needs. Reach out to us today to get started!