How to Properly Mount Reducers on Different Pipe Materials

Reductions on other pipe materials are a critical point when transitioning between polyethylene pipes and metal systems, where sealing issues often occur. Proper installation requires not only precise tools but also strict adherence to the procedure for preparing pipe ends and tightening connecting components.

Choosing the correct type of reduction and material

When selecting a brass compression fitting, it is crucial to consider the type of polyethylene (PE80 or PE100) and the operating pressure in the system, as an incorrect type of nut can lead to plastic deformation. We recommend always choosing a compression fitting with a stainless steel ferrule for higher corrosion resistance and longer joint life compared to standard steel nuts.

An incorrect material for the nut, for example, ordinary steel without surface treatment, can create a galvanic cell under moist conditions and cause rapid corrosion around the threads, leading to heat and water leakage.

Critical preparation of the polyethylene end before installation

The success of the entire joint depends on a perfectly prepared cut, which must be perfectly perpendicular to the pipe axis and free of all sharp edges and burrs. If the cut is skewed by more than 1 degree, uneven pressure will be exerted on the sealing ring, causing immediate or delayed leakage under pressure.

• Use a special pipe cutter for PE pipes, not ordinary saws or pliers.
• Ensure the pipe end is clean of dirt, grease, and moisture before inserting into the fitting.
• Check the internal diameter of the pipe to ensure it matches the nominal diameter for the given pressure class.
• Always remove external burrs with a knife to prevent damage to the sealing ring during installation.

In practice, we have seen a case where technicians used a wood saw to cut thin-walled pipes, which led to the formation of microcracks and subsequent cracking of the joint after the first heating of the system.

Installation procedure and insertion depth setting

An important step is achieving the correct insertion depth of the pipe into the fitting body, which is defined by the manufacturer's marking or a measuring scale on the valve body. The pipe must be inserted all the way to the stop, with minimal gap between the end of the pipe and the bottom of the body to ensure solid support.

If this depth is not maintained, the pipe may be pushed back under pressure, breaking the seal and causing water to leak from the joint. Always mark the insertion depth on the pipe with a marker or permanent marker before installation.

This step is the most common cause of problems in new constructions, where installers rush and ignore visual checks of depth.

Tightening the joints and checking torque

Tightening the nut on a brass compression fitting requires an exact torque, which should be specified in the technical data sheet for the specific model, usually ranging between 15 and 25 Nm for standard diameters. Over-tightening can cause the polyethylene to crack or deform the sealing ring, while under-tightening will inevitably result in fluid leakage.

Always use a torque wrench instead of a regular wrench to avoid accidentally exceeding the maximum force value. For larger diameters above DN25, we recommend tightening in three stages, with each stage representing one-third of the final torque.

Difference between compression and crimping systems

Compression fittings allow disassembly and reassembly without the need for a special crimping tool, which is an advantage for maintenance and repairs of existing systems. Crimped joints, on the other hand, offer higher security and resistance to vibrations, as they create a monolithic connection that cannot be mechanically loosened.

When choosing between these two types, consider the available space for manipulation and the frequency of system intervention. For permanent embedded solutions in walls, crimped joints are ideal, while for visible piping in boiler rooms, compression fittings with the possibility of adjustment are suitable.

It is important to note that crimped joints require a one-time application and any intervention requires cutting out the old joint and installing a new one.

Common errors in operation and maintenance

One of the most common errors is ignoring the thermal expansion of polyethylene, which is several times higher than that of metal pipes, which can lead to loosening of compression joints during cyclic heating and cooling. The system should be designed to allow some flexibility near the joints and should not be used as a rigid load-bearing structure.

• Do not use sealing tapes on polyethylene parts intended for sealing threads, only on metal threaded parts.
• Do not embed pipes in concrete without protective sleeves that allow pipe movement without damage.
• Regularly check the tightness of the joints after the first year of operation, as plastic can "relax" and loosen the seal.
• Avoid direct sunlight on exposed areas, which degrades the surface of the PE pipe and reduces its strength.

Preventive tightness checks using soap or gas detectors are essential at least once a year, especially in areas with high humidity.

Preparation of the internal surface and removal of burrs

An essential step that is often overlooked is thoroughly cleaning the inner edge of the pipe after cutting. If microscopic burrs or plastic fibers remain on the surface, they can cut through the sealing gasket from the inside when the nut is tightened, leading to slow leaks.

Frequently asked questions

Can I use standard sealing tape on PE pipes?

No, sealing tapes are intended only for metal threaded connections and are not used at all on polyethylene parts, as they interfere with the function of the sealing gasket.

How long will a brass fitting last on a PE pipe?

If installed correctly and parameters are followed, it should last the entire lifetime of the installation, i.e., several decades, unless mechanical damage occurs.

What to do if a leak appears after tightening?

Immediately turn off the water flow, check the depth of the pipe insertion, and if necessary, cut off the pipe and install a new piece with a new fitting.

Proper installation of reducers on other pipe materials ensures long-term and trouble-free operation of your heating system, so pay attention to each detail of the process.

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.