John Guest Stem Reducer

• Product type: Push-fit x stem reducer, unequal straight connector
• Manufacturer: John Guest
• Body material: Acetal copolymer
• Seal material: Nitrile O-ring
• Maximum working pressure: Up to 10 bar
• Temperature range: -20°C to +70°C
• Connection method: Push-fit, demountable
• Compatible pipe materials: Nylon and powder-coated aluminium
• Application media: Compressed air, inert gases, vacuum and potable liquids
• Country of manufacture: United Kingdom

This reducer fitting is designed to connect two pipes of different diameters within compressed air and pneumatic systems. The push-fit design allows for fast, secure connections without the need for tools, sealing compounds or hot works, significantly reducing installation time compared to traditional jointing methods.

A precision collet locking mechanism grips each pipe securely without deforming the pipe or restricting flow, while the integrated nitrile O-ring delivers a reliable, airtight seal. The fitting is fully demountable, allowing systems to be easily modified, extended or maintained with minimal disruption.

Manufactured from tough engineered plastic, it is compatible with John Guest nylon and powder-coated aluminium air pipe. Its versatility makes it suitable for a wide range of industrial, workshop and commercial compressed air installations.

• Unequal pipe connection: Allows smooth reduction between different pipe diameters
• Instant push-fit installation: No tools, heat or sealing agents required
• Demountable design: Simplifies maintenance and future system modifications
• Secure collet locking system: Holds pipes firmly without damage or flow restriction
• Airtight sealing: Nitrile O-ring ensures dependable, leak-free performance
• Wide compatibility: Suitable for plastic and soft metal pipe materials
• Multi-application use: Ideal for compressed air, inert gases, vacuum and potable liquids
• Made in the UK: Manufactured and assembled to consistently high quality standards

Installing a John Guest Reducer is designed to be straightforward and user-friendly, following these simple steps:

1. Cutting the Pipe: Ensure both pipes (the larger and smaller ones) are cut squarely. This is critical for a proper fit. Use a John Guest pipe cutter for rigid nylon pipes. For aluminium pipes, utilise aluminium pipe cutters. After cutting, remove any burrs or sharp edges to avoid damaging the O-Ring. This step is important to maintain the quality of the seal.
2. Making the Push-Fit Connection: Slide the larger pipe into one end of the reducer and the smaller pipe into the other end. Push each pipe up to the pipe stop in the reducer. Make sure the pipes are aligned correctly within the reducer to ensure an effective and leak-free connection.
3. Checking the Connection: After inserting the pipe, pull it slightly to ensure the connection is secure. This test confirms that the fitting is properly engaged. Before using the system, conduct a thorough test to ensure there are no leaks and that all connections are secure.
4. Disconnecting the Fitting: Ensure the system is depressurised before attempting to disconnect. Push the collet towards the fitting to release the pipe. This step is crucial for a smooth disconnection. Carefully remove the pipe from the fitting.