Installation Instructions
PEX Fittings Product Range

Last Updated

December 11, 2020

Flowflex reserve the right to alter the product ranges and specifications associated with its products without prior notice

Flowflex PEX fittings is our solution for connecting brass fittings to PEX pipe. PEX Fittings, 16mm to 20mm, come manufactured with an insert and are supplied with a split olive to allow for a firm joint. Our PEX range brings quality and reliability to your localised water system and is suitable for use central heating and underfloor heating systems. Our PEX system range includes Brass Fittings, Valves, Manifolds, Pipe and Pipe Sheaths for a full system solution.


  • Domestic
  • Commercial


PEX Pipe Specifications

Ensure the pipe conforms to the specification, and that the pipe outer diameter matches the size of the fitting. Ensure that both the pipe and fitting are clean, in good condition and free from any damage or imperfections.

  • PEX Pipe supplied is eligible to bear the CSA mark.
  • PEX Pipe supplies is eligible to use the SKZ - testing & inspection mark.
  • PEX Pipe supplied is eligible to use the EBETAM (MIRTEC) mark of conformity.
  • The material of the PEX Pipe is WRAS Approved.


  • PEX Pipe
  • Compression PEX Fitting
  • Adjustable Spanner
  • Pipe Cutting Tool
  • Internal & External Pipe Deburring Tool


Cut Your Pipe to Size

Cut Your Pipe to Size

Cut your pipe cleanly across the tube diameter.

It is important your pipe accurately. Failure to do so could impact on the quality of your jointing.
At this point you should be careful to ensure no pipe residue, dirt or grit is present near the joint.

Assemble the fitting around the tube

Assemble the fitting around the tube

Remove the compression nut and the split olive, then put the nut on the tube, followed by the split olive. Insert the tube end up to the fitting's tube stop. Slide the split olive olive and the nut down to the fitting body. Tighten the nut using your fingers to secure the fitting in place.

PEX pipe requires a pipe support liner, which should be pushed fully into the bore of the pipe. In the case that the pipe support liner is difficult to insert, you can make a small chamfer with a sharp knife.

Tighten the nut

Tighten the nut

Tighten the nut further using open ended or adjustable spanners, using the spanner flats incorporated into the fitting body and nut. The second spanner must be used to prevent the fitting rotating as the nut is tightened..


We recommend that all systems are throughly tested upon completion. Whenever possible, completed systems should also be flushed to remove debris.

Hydraulic Installations

In hydraulic based installations, the system may be tested to 1.5 times the working pressure of the system. If higher test pressures are required, then please contact us for further advice.

Any Questions?

Our team is available for you anytime.