The Advantages of Capillary Fittings: A Comprehensive Guide

Capillary fittings, also known as Soldered fittings, are a popular choice in plumbing and heating systems due to their reliable, strong, and leak-proof connections. Used extensively in both residential and commercial applications, these fittings can either be brazed or rely on capillary action to draw solder into the joint, creating a durable bond between pipes.

In this guide, we will explore the key advantages of capillary fittings and why they are a trusted option for professionals and DIY enthusiasts alike.

Capillary

Flowflex Capillary fittings are designed for precision and reliability in copper pipe connections. Featuring a capillary action for secure, leak-free joints, they ensure ease of installation and longevity. Ideal for domestic and commercial applications, these fittings provide a neat, robust, and corrosion-resistant solution for HVAC systems.

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What Is A Capillary Connection?

A Capillary Connection is a type of joint used in plumbing and heating systems that connects a fitting and a pipe through soldering or brazing.

In both methods, a narrow gap exists between the fitting and the pipe. When heat is applied, the filler metal melts and is drawn into the gap through capillary action, forming a strong bond between the two components.

Brazed joints are stronger than soldered ones, as they require higher temperatures and use different filler metals. Soldering utilises solder, while brazing uses a brazing rod, making brazed connections more robust but also more demanding in terms of heat and skill.

Where Are Capillary Fittings Used?

Capillary fittings are used in a wide range of applications across plumbing, heating, and gas systems due to their strong, reliable, and leak-proof connections. Here are some common areas where capillary fittings are used:

They are commonly found in:

• Domestic Plumbing

• Heating Systems

• Gas Installations

• Refrigeration and Air Conditioning

• Industrial Applications

What Types of Capillary Fittings Are there?

End Feed Fittings

End Feed fittings are a type of capillary fitting that uses capillary action to draw solder into the joint between the fitting and the pipe, creating a strong, reliable seal. End Feed fittings are distinct because they require the installer to manually apply solder during installation.

End Feed

Discover Flowflex End Feed fittings for quick, reliable copper pipe connections. Lightweight and easy to install, they offer compact, neat solutions for any space. Manufactured to BS EN 1254 standards and WRAS approved, these fittings ensure high quality and secure, leak-free joints. Click to explore our full range.

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Solder Ring Fittings

Solder Ring fittings come pre-loaded with a ring of solder inside the fitting, making the installation process simpler and more consistent compared to traditional End Feed fittings. When heated with a torch, the pre-installed solder melts and creates the soldered joint. Solder Ring fittings are particularly advantageous for those looking to streamline the installation process while maintaining high-quality results.​

Solder Ring

Discover Flowflex Solder Ring Fittings, designed for quick and easy installation. Lead-free and pre-soldered, they fit perfectly in tight spaces, ensuring secure connections. Available in sizes from 8mm to 54mm, these fittings are WRAS approved and guaranteed for 25 years. Click to explore our high-quality, reliable solutions.

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What Are The Advantages Of Capillary Fittings?

• Strong, Permanent Joints
  Soldered joints create a durable, leak-proof seal that can withstand high pressure and temperature changes.

• Can Support Higher Pressures
  Depending on the choice of solder, Capillary Fittings can reach pressure ratings of PN25.

• Environmentally Friendly Material
  Copper is a sustainable and recyclable material, making capillary fittings an environmentally friendly option.

• Compact Design
  Soldered fittings are sleek and low-profile, making them ideal for exposed installations where aesthetics matter or tight spaces where access is limited.

• Cost-Effective
  Generally cheaper than other types of fittings, making them popular for large installations.

• Highly Reliable
  Minimal risk of leaks when installed correctly due to the solid bond between the fitting and the pipe.

Considerations

Safety

The use of an open flame during installation can pose fire risks, especially in confined or flammable areas. Always take appropriate precautions such as ensuring good ventilation, keeping flammable materials clear, and having fire safety equipment nearby.

Use The Correct Solder and Flux

It’s important to choose the correct solder and flux for your specific application. For potable water, use lead-free solder, while specialised solder or brazing may be necessary for other applications.

Importance of a Skilled Installation

A secure and leak-free capillary joint requires good technique. Skilled labour is essential to correctly apply heat, ensuring the solder fully bonds with the fitting and pipe for a reliable connection.

Conclusion

Capillary fittings offer numerous advantages that make them a preferred choice for plumbing and heating installations. Their strong, reliable connections, proven durability, cost-effectiveness, and compact design make them suitable for a wide range of applications. Whether you’re working on a new installation or repairing existing pipework, capillary fittings provide a dependable, professional finish that stands the test of time.