which crimping tool do I need for 17 mm PEX pipe

Crushing PEX pipe with a diameter of 17 mm is one of the most common operations during the installation of floor heating and piping systems in apartments, where high reliability and fast assembly are required. Choosing the right crimping tool is not only a matter of price, but primarily about the safety of the entire system and compliance with technological standards to achieve durable and tight connections.

Choosing the correct type of crimper according to the mechanism

For PEX pipe with an outer diameter of 17 mm, electric hydraulic or manual mechanical crimpers using specific dies precisely adapted to this dimension are standard. Electric crimpers offer higher consistency in results and often have a built-in chip for recording data about the connection, which is essential for guarantees in professional buildings.

• Battery-powered electric crimpers are ideal for areas without access to electricity, such as renovations of older apartments.
• Hydraulic crimpers connected to a compressor ensure maximum crimping pressure for demanding conditions and long-term use.
• Manual lever crimpers are an economical choice for smaller volumes of work, but they require precise control of the force by the operator.

Technical parameters and crimping die

A key factor is the use of an accurate crimping die marked for the size 17 mm, which ensures the deformation of the brass sleeve of the fitting to the required value. Using an incorrect die, for example for 15 mm or 22 mm, will result in either insufficient compression, causing water leakage, or damage to the material due to excessive force.

For standard applications in heating systems, it is sufficient if the crimping tool achieves a minimum crimping pressure of approximately 12 to 14 tons, which is standard for most brands such as Wavin, Rehau or Uponor. For professional projects, we recommend checking whether your crimper allows calibration and has a function to indicate the completion of the process, so you can avoid human error.

Application to specific types of connections

When working with 17 mm pipe, you will most often need to crimp elbows, T-pieces or straight couplings, each of which requires the correct orientation in the crimping head. For directional changes, it is suitable to use a high-quality 90° PRESS elbow - for PEX pipe - 17x17, which must be crimped so that the crimping point is exactly in the middle of the bent section.

For branching the pipe, use a T-piece PRESS - for PEX pipe - 17x1/2"Fx17, which requires stable gripping to prevent it from shifting and changing the branching angle during crimping. To terminate the pipe or connect it to another system, use a coupling PRESS - for PEX pipe - 17x17, which must be fully inserted to the stop before starting the process.

Practical steps for safe installation

Installation should always begin with cutting the pipe using special cutters, which ensures a clean, perpendicular cut to the pipe axis, then remove the internal and external burrs and ensure the surface is clean. Insert the pipe into the crimping fitting until it reaches the stop, making sure you can see the gap between the end of the pipe and the internal neck, which is a visual check of correctness.

After placing it in the die, start the crimping process and wait for the automatic shutdown of the machine or confirmation signals that the required pressure has been achieved. Never remove the crimping tool before the crimping process is completely finished, as this can lead to micro-cracks in the brass body.

Comparison of crimping systems for 17 mm PEX

In practice, we often encounter the question of whether a simple manual crimper is sufficient or if an investment in an electric model is necessary. When working with a diameter of 17 mm, which is standard for floor heating in apartments and smaller family homes, it is important to consider not only the crimping force, but also ergonomics and speed.

Manual lever crimpers (e.g. brands Kärcher, Rixen) are sufficient for this size if you are working on smaller areas up to 100 m². They use a mechanical lever that multiplies your force, but they require physical fitness and precise alignment of the crimper on the fitting. In contrast, battery-powered electric crimpers (e.g. Uponor E-Lite, Wavin L-System) provide constant pressure regardless of operator fatigue, which is critical for long pipe runs in underfloor heating.

Critical parameters of the crimping head and die

When selecting a die for 17 mm pipe, the only factor should not be the marking "17 mm". You must pay attention to the type of crimping system, as there are different crimping technologies: classic smooth crimping and crimping with grooves (for special fittings). Most common PEX systems (PEX-a, PEX-b, PEX-c) use smooth brass fittings, which require a crimping die with an exact rectangular or oval shape.

An important detail is the die tolerance. If the die is too worn, the crimped joint may have insufficient deformation diameter, which can lead to water leakage under pressure. Therefore, it is necessary to regularly check the condition of the dies using a calibrated measuring tool. For 17 mm pipe, the standard gap after crimping is approximately 18.5 to 19 mm (depending on the manufacturer), with a deviation over 0.2 mm indicating a problem.

Marking and identification of dies

Professional installers always check whether the diameter and material type are clearly marked on the die. Some cheaper dies may have only numbering, which increases the risk of error during fast installation. The correct die for 17 mm must be made of hardened steel resistant to high pressure, so that its shape does not deform after repeated use, which would then spoil all the joints.

• Check that the die is clean and free of dirt before placing it on the crimper.
• Make sure the die fits on the crimping head without any free movement.
• Use original or certified dies for different brands (Wavin, Rehau, Uponor), as tolerances of brass bodies can slightly vary.

Safety aspects and standards during crimping

Crimping PEX 17 mm pipe is not only about mechanical joining, but also about compliance with STN EN ISO 15494 standards, which define requirements for crimping systems. An incorrect procedure not only risks water leakage, but also damage to the PEX pipe itself, which can lose its flexibility and become brittle at the joint.

One of the common mistakes is crimping a fitting that is not fully inserted into the bottom. Although it may look like a small gap, under the pressure of the heating system (typically 1.5 to 3 bar), the joint will gradually loosen. Another common mistake is crimping a previously damaged fitting, for example scratched or with a damaged sealing rubber ring (if part of the fitting).

For professional work, it is also essential to use a crimping tool that has a built-in chip or the possibility of connecting to an external database system. These systems record the date, time, pressure value and operator ID for each individual joint. This is now a requirement for obtaining a warranty on the entire installation from pipe manufacturers.

Maintenance and storage of crimping tools

In order for your crimping tool to serve you for years, it is necessary to maintain it properly. After each season or completion of a major job, it is advisable to clean the crimping head and dies from metal shavings and dirt. Use a soft cloth and possibly light oil for protection against corrosion, but never use aggressive chemicals that could damage seals in the hydraulic system.

Batteries of electric crimpers must be stored in a dry environment at room temperature. Long-term storage of a completely discharged battery can lead to its irreversible damage. Before each use, check the condition of the battery and the corresponding cables to ensure they are not damaged. With manual crimpers, check whether the lever moves smoothly and does not jam due to worn bearings.

Die regeneration is another step that requires a specialist. If you feel that the crimping is not as firm as before, it is likely time to replace the dies. Replacing the die for 17 mm is cheaper than repairing damaged underfloor heating due to a leaking joint.

Common questions

Can I use a universal crimper for different diameters?

No universal crimper is suitable for all sizes, so it is necessary to change the dies for each diameter, including 17 mm, to maintain the accuracy of crimping.

How long does a crimped joint on PEX pipe last?

With proper installation and adherence to the parameters of crimping tools, the lifespan of the joint is comparable to the lifespan of the pipe itself, i.e. more than 50 years.

What to do if the joint leaks after crimping?

Never try to fix a leaking joint by crimping it again; such a joint is unusable and must be replaced with a new one, because the metal has already lost its elasticity.

To conclude, it can be said that an investment in a quality crimping tool with precise dies for 17 mm pipe will pay off in the form of minimized service interventions and long-term reliability of the heating system. The correct technology and strict adherence to procedures are the foundation for professional heating system implementation, which will function without problems for decades.

Do you have a question about this topic?

Not sure or dealing with a specific situation in your home? Write to us - we are happy to help.