PEX-AL-PEX piping 26 x 3 for heating, underfloor heating and water

Product detailed description

This PEX-AL-PEX piping is commonly used in residential, commercial and industrial buildings for central heating, underfloor heating, and domestic hot and cold water distribution. Its multi-layer design combines the flexibility and corrosion resistance of plastics with the structural stability of aluminium. Installers frequently work with this material in both new constructions and renovation projects where high thermal efficiency and mechanical strength are required.

The pipe’s low thermal expansion coefficient and smooth internal surface reduce the risk of leaks and scaling. It is compatible with screw and compression fittings and can be bent manually or with spring tools depending on the radius required. The oxygen barrier prevents oxidative degradation of the system, ensuring reliable performance over decades.

Technical parameters

Installation and connection

Installation begins with measuring and cutting the pipe using a dedicated pipe cutter for clean edges. The minimum bending radius without tools is five times the outer diameter, while a spring allows a tighter bend of three times the outer diameter. Each joint should be checked for tightness and alignment after assembly. Common mistakes include using incorrect fitting types, insufficient tightening, or failing to account for thermal expansion during layout planning.

Compatibility and accessories

This pipe is designed to work with screw fittings and compression couplings. For complete installation, additional components such as valves, manifolds and insulation may be required. A related alternative is the PEX-AL-PEX 20 x 2 pipe, which offers similar properties but with smaller dimensions suitable for compact systems or lower flow requirements.

Technical background for designers

The PEX-AL-PEX construction consists of a cross-linked polyethylene inner layer, a 0.30 mm thick aluminium middle layer and another cross-linked polyethylene outer layer bonded with adhesive. The oxygen barrier prevents ingress of dissolved oxygen, which can cause corrosion in metal components of the system. When integrated into a closed-loop heating system, the pipe contributes to uniform heat distribution and long-term energy efficiency due to its low thermal losses and smooth flow characteristics.

Service and operation

Maintenance typically involves periodic visual inspections for signs of wear or damage, especially at joints and bends. The system should be flushed if there are concerns about internal deposits affecting flow rates. No specific service intervals are recommended beyond routine checks, and the absence of internal corrosion means long-term reliability is largely dependent on correct installation and environmental conditions.

Frequently asked questions

Can this pipe be used in underfloor heating systems?
Yes, the Wigell PEX-AL-PEX 26 x 3 is suitable for underfloor heating applications due to its flexibility, thermal stability and resistance to scaling.

What fitting types are compatible with this pipe?
Screw fittings are recommended for connecting the pipe. Compression fittings may also be used, provided the manufacturer specifications are followed.

Is an oxygen barrier included in the design?
Yes, the pipe includes an oxygen barrier to prevent oxidative degradation within the system, enhancing the longevity of metal components like radiators and boilers.

How does the thermal expansion coefficient affect installation?
The 0.026 mm/m·K expansion coefficient must be considered when designing the layout to ensure sufficient space for expansion and contraction, particularly in large-scale installations.