< Expert Advice | 19.02.2018

Perfect fit: press-fitting systems

Perfect fit: press-fitting systems

Press fitting can help installers produce secure and long-lasting leakproof joints. Guy Hadwin, marketing manager at Rothenberger, outlines how to go about it.

The principle of press-fitting systems is very simple: to produce secure, long-life, leakproof joints in a variety of pipe and tube materials in a comprehensive range of working sizes.

Compared with traditional jointing techniques, productivity is significantly improved, greatly reducing installation times and increasing working flexibility and lowering overall costs. With press-fitting systems, a secure, aesthetically pleasing, permanent joint is produced without soldering, preventing unintentional damage and avoiding the requirement for a hot work permit.

The all new Romax® Compact TT from Rothenberger is 8cm smaller and 400g lighter than its predecessor, making it the smallest 18V pressing machine on the market. Powered by the new powerful 18V Li-ion 4ALL battery platform, the TT Compact piston can deliver an impressive 19kN/30mm force, capable of powering pressing jaws 12mm to 35mmØ (system dependent).

As with any system, the integrity of the joint is only as good as the preparation and quality of materials and tools used. By following these simple step-by-step instructions and choosing the correct press-fitting machine, jaws and compatible fittings, perfect joints can be made time after time.

STEP 1: Cut the pipe
Use a Rothenberger or similar pipe cutter with a new or undamaged wheel. It is important to ensure that the pipe is cut completely square. Tube ends should be clean and free from scratches or damage on the end that fits inside the fitting.

STEP 2: Remove burrs
Make sure that the internal and external tube ends are free from burrs or sharp edges by using a deburring tool. Then wipe the tube end clean to avoid damaging the O-ring when the tube is inserted into the fitting.

STEP 3: Ensure the O-ring is seated and lubricated
Before inserting the copper tube, ensure that the O-ring is seated correctly, free from damage and lubricated. If not lubricated, a small amount of water can be used.

STEP 4: Mark insertion depth
In order to make the perfect joint, the tube must be correctly inserted into the fitting until it reaches the tube stop. Marking the insertion depth on the tube will ensure that any movement is detected, which is important if the joints are to be pressed at a later time.

The pressing operation should only be undertaken when the tube has reached the tube stop and the previously marked tube realigns with the fitting.

STEP 5: Complete the joint with the pressing tool
Ensure that the correct size jaw for the fitting is inserted and locked into the tool. The jaws must be placed squarely on the fitting. Depress the trigger to begin the compression cycle of the tool.

The cycle is complete when the mouth of the fitting is fully enclosed by the jaws, and the internal piston returns to the start position. With the Rothenberger Compact TT, this cycle takes only three seconds. Now release the jaws from the fitting. The joint is now complete.

For further information, visit www.rothenberger.co.uk


YOUR QUESTIONS ANSWERED

What grades of copper tube do the fittings suit?

Annealed (R290), half hard (R250) and soft (R220)plumbing tube to EN 1057.

Can you rotate a press fitting once installed?

No. Once pressed, they cannot be rotated.

Can press joints be dismantled and reused?

No, this is a permanent installation.

When using older pipes, how do you prepare the surface?

The surface should be prepared in the same way as with new pipe. And provided there is no corrosion, the tube dimensions comply with EN 1057 and the fittings are installed correctly, there are no leaks.

What are the application limitations?

It cannot be used where pressures are greater than those recommended or where corrosive fluids/gases need to be transmitted.

What pressure do you need to test to and for how long to show any leaks?

Unpressed fittings are identified by pressurising the system with a pressure range of 1 bar to 5 bar for water and 22 mbar to 3 bar for gas. Final testing of the system should be conducted in accordance with the Water Regulations Guide and/or the Building Regulations.

Can it be used with medical gas?

No, it’s not recommended for use with medical gas.

Does the clipping of fittings/jobs differ from a welded copper application?

No, the same type of clips can be used.

Can the fittings be used on compressed air or oil lines?

Water fittings are recommended for compressed air (oil free). Press gas fittings are suitable for all compressed air applications.

What are the benefits of press fittings?

Fast, simple and reliable installation.

Can press fittings be installed on pipes where the mains line won’t shut off?

Yes, the fitting can be used in wet conditions and after pressing will provide a watertight joint.

Can press fittings be used on chrome tube?

Yes, provided that the tube complies with EN 1057. However, it is recommended to test a piece first as some splitting of the chrome may occur.

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