Fusion, Joints and Repairs

There are different ways to join ALMATHERM pipes and fittings:

  1. Fusion Welding: pipe and fitting are welded together. Both are made of PP-R so that no additional welding material is required. 

  2. Threaded Fittings: both Male and Female threads are available. The threads confirm to DN EN 10226-1 and are made of CW617N (CuZn40Pb21) brass. Can be supplied in yellow brass colour and/or nickel plated.

  3. Flange connections: a flange adaptor is joined to the pipe ends and connected then together with steel flanges on both sides. In case of need, connections can be detached at any time. Application range for pipe sizes >40mm ø. Sizes confirm to DIN 2501-PN16.

  4. Union Fittings: available for a wide range of applications and sizes




Fusion Tool Operating Guidelines

       -          Socket Fusion Welding Tool

-          Electro fusion Welding Kit

-          Desktop Welding Machine


Four-Step Fusion Process:

Step 1

Cut pipe to the required length using a cutter, mark the welding depth on the pipe, ensure that the indicator light on the welding tool signals that the tool is hot enough (260°C) for welding.

Step 2

The tip of pipe to be welded is shaved by a special shaver to remove outside PP-R layer and aluminium foil (this step is applicable only to the STABI pipes).

Step 3

Push the pipe and fitting into the welding adaptors, applying even strength at both ends. Do not twist or turn the pipe and fitting while pushing. Wait until the heating time is reached.

Step 4

When the welding heating time is reached, remove both the pipe and the fitting together, again without twisting or turning while pulling out of the welding adaptor. Almost immediately, push both pipe and fitting together until the depth is reached. It is possible to adjust the joints for more than 5 degrees during this time. Joint is now complete.



Welding Depth, Heating, Welding and Cooling Time

The table below provides the necessary information for a good welding joint for various ALMATHERM pipe and fitting sizes (applies to STABI and FASER pipes also).


Note: Heating time starts when both pipe and fitting are pushed into correct depth. Welding time begins when joints are connected. Cooling time is the time taken for the joint to be completely cured. Never reduce cooling time by pouring water or by other means.



 Homogeneous Joints

The result of socket fusion or electro fusion is a homogeneous joint. Such, is one of the biggest advantages of using ALMATHERM system. 

-          100% leak proof

-          No maintenance

-          Visual inspection possible

-          Perfect for concealed installation that needs corrosion free joining system

-          Does not cause a reduction in the flow at the joint




Pipe Repair

Pipe repair may be carried out by one of the following methods:


Pipe with nail holes (not concealed)

If the damaged part of the pipe is not concealed yet (before the pressure test is conducted), the recommended procedure is to cut out the part and replace it with a new part through normal welding of a socket.



Pipe with nail hole (concealed)

Using a repair patching stick – as shown below.

Pipe with two through holes (concealed)

Using Electro fusion Fittings – as shown below:

Cut the damaged pipe perpendicularly, by a length equal to that of the corresponding electric socket plus 2cm.

Remove the section of the damaged pipe.

Carefully clean the surface of the two pipe sections to be joined using sandpaper and solvent liquid and wait until parts of the pipe are perfectly dry.

Remove the inner stops from 2 electric sockets.

Fully insert the electric sockets into the pipe sections.

Cut a pipe section having the same diameter and length as the damaged one.

Fit in the place of the previous one. Make the 2 electric sockets slide towards the middle of the new pipe piece, by a section equal to half the length of the socket.

Weld the socket using an electro fusion welding kit.


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