When designing or upgrading a plumbing or irrigation system, one of the most important choices you’ll face is selecting the right type of check valve. Check valves are essential components that prevent backflow, ensuring that water or other fluids move in only one direction through your piping system. Two of the most popular types available in the market today are PVC Spring Check Valves and PVC True Union Check Valves. Both offer unique advantages, but each is better suited for specific applications.

Let’s take a detailed look at how these two types of valves compare, their pros and cons, and why 247Garden’s line of PVC check valves—from 1/2 inch up to 4 inches—is a solid choice for any project.

What Is a PVC Spring Check Valve?

A PVC Spring Check Valve uses a spring-loaded mechanism to allow flow in one direction and automatically closes when the flow stops or reverses. This makes it a self-actuating valve that is extremely useful in systems where a quick shut-off is necessary to prevent backflow.

Advantages of PVC Spring Check Valves:
One of the biggest benefits of a spring check valve is its fast response time. The built-in spring closes the valve quickly as soon as the pressure drops, making it ideal for systems that experience sudden stops in flow. The compact design makes it easier to install in tight spaces, especially in vertical runs. Since it closes quickly, it also reduces the risk of water hammer—a pressure surge caused when water in motion is forced to stop or change direction suddenly.

Disadvantages of PVC Spring Check Valves:
While spring check valves are reliable, they do have a few downsides. The internal spring requires more pressure to open, which can restrict flow in low-pressure systems. They’re also typically not serviceable—once they clog or wear out, you may have to replace the entire unit. Without union fittings, removal often requires cutting the pipe, which can be inconvenient during repairs or system upgrades.

What Is a PVC True Union Check Valve?

A PVC True Union Check Valve features a swing or flapper mechanism and comes with union fittings on both ends. This design allows the valve to be removed easily for inspection, cleaning, or replacement without cutting into your piping system.

Advantages of PVC True Union Check Valves:
Maintenance is where true union check valves really shine. The union ends make them easy to install, remove, and service. They are ideal for systems that require regular inspection or cleaning. Additionally, they have a low-pressure drop because the flapper opens easily and allows for unrestricted flow, making them suitable for low-pressure systems.

Disadvantages of PVC True Union Check Valves:
Because of the union fittings, these valves are bulkier than spring check valves, requiring more installation space. They are also slower to close than spring-loaded valves, which may allow minor backflow or contribute to water hammer if not installed properly. They may not be the best choice for vertical down-flow applications because gravity may not always close the flapper quickly enough.

Which One Should You Choose?

The best choice depends on your specific use case. If you’re working in a compact space or need rapid shut-off in a vertical pipe configuration, a spring check valve may be your best bet. On the other hand, if you want easy maintenance and low-pressure operation, a true union check valve is the smarter choice.

For permanent installations that aren’t likely to require frequent servicing, a spring check valve offers simplicity and reliability. For setups where access and maintenance are priorities—like hydroponic systems, aquariums, or industrial water processing—a true union check valve provides flexibility and long-term value.

247Garden Check Valve Solutions: Available from 1/2" to 4"

247Garden offers high-quality check valves in both spring and true union styles, built from Schedule 40 or Schedule 80 PVC for dependable performance.

Spring Check Valves from 247Garden:
Available in sizes from 1/2 inch up to 4 inches
Designed for quick installation in irrigation, aquaponics, hydroponics, and light industrial systems
Built with corrosion-resistant internal spring and quality seals for reliable one-way flow
Compatible with both horizontal and vertical installations

True Union Check Valves from 247Garden:
Available in 1/2 inch through 4 inches
Includes EPDM or Viton O-rings for chemical resistance and longevity
Union fittings allow easy disassembly for cleaning or part replacement
Ideal for long-term use in systems requiring regular inspection or service

Conclusion

Both types of check valves have their place in modern plumbing and water management systems. The decision between a spring check valve and a true union check valve should be based on how you plan to use the system, whether regular maintenance is needed, the space available, and the pressure range.

Whatever your application, 247Garden has the PVC check valve solution you need. From residential irrigation to commercial water filtration, our durable fittings—available in a wide range of sizes—are engineered to keep your systems flowing smoothly and safely.

If you’re unsure which size or type is best for your system, 247Garden can help you select the right product to match your project’s specifications.

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