Viega Megapress S and S XL: FKM up to 140 °C, district heating and the large sizes up to 4 inch

What distinguishes Megapress S from standard Megapress

The connector is the same: unalloyed steel 1.0308 with zinc-nickel coating, cutting ring and separating ring in the bead, plus the SC-Contur that makes a forgotten press visible during the leak test. The difference sits in the sealing element. Instead of the EPDM profile sealing element, Megapress S carries an FKM sealing ring (fluoroelastomer) with increased cord thickness – recognisable by the white dot on the press end and the matt black surface of the element. FKM tolerates higher temperatures and is resistant to oils and many solar fluids where EPDM swells or embrittles.

From this follow the characteristic values: operating temperature up to 140 °C instead of 105 °C, operating pressure unchanged at 1.6 MPa (16 bar). Pipes, sizes ⅜–2 inch, press jaws and press rings are identical to the standard system – Megapress and Megapress S are pressed with the same tools and can be combined in one plant, as long as each section carries the right sealing element for the medium.

What does not work even with FKM: drinking water (the system is not intended for it and is marked accordingly) and fuel gases (for those, Megapress G with HNBR). For solar installations Viega expressly recommends FKM when the collector type is not yet known when the connection line is laid.

Fields of application and limits per use

The 140 °C do not apply across the board but per field of application with its own conditions. The instructions for use summarise them as follows:

District heating is the reason Megapress S is found in the house connection room: from the building entry onwards there are thick-walled steel pipes that used to be welded. With the connection to AGFW FW 524, transfer station, primary circuit and distribution up to 2 inch can be pressed cold – without a welding permit in an occupied building. The network operator's approval (technical connection conditions) remains a prerequisite.

Megapress S XL: 2½ to 4 inch

The XL sizes exist exclusively as Megapress S, that is with FKM sealing element. They close the gap between the press connector for installation and the methods of pipeline construction: DN 65, 80 and 100 are the sizes of the distribution lines in industry, heating plants and cooling installations, where the welder could not be replaced until now. Approved are – as in the standard system – seamless and welded steel pipes to EN 10255 and EN 10220 with EN 10216-1 or EN 10217-1, black, galvanised, industrially painted or powder-coated:

Striking is the wide wall-thickness range for seamless pipe: Megapress S XL presses 4-inch pipes from 3.6 to 32 mm wall – so also the thick-walled grades of plant construction, not just threaded pipe. For welded pipe the upper limit is 4.5 to 5.4 mm. Whoever works in existing buildings measures outside diameter and wall and compares with the table; coated pipes must not exceed the maximum outside diameter including the coating.

Tooling: press ring and Press Booster

The XL sizes are pressed not with a press jaw but with a Megapress XL press ring, which is coupled to the system press tool via the Pressgun Press Booster. The Booster multiplies the tool's force for the large circumference; Viega states in the instructions for use which tools (among others types PT2, PT3, Pressgun 4E/4B, 5, 6) are approved with Press Booster and XL press rings DN 65 to DN 100. The space requirement of the press rings and the minimum distances between connectors, to walls and to weld seams (3 × D) are given in tables in the instructions for use and belong in the planning – an XL press ring needs more room than a weld seam.

Flange adapters up to PN 40

For connection to valves, pumps and existing stock there are, in 2½, 3 and 4 inch, three fixed-flange adapters in steel 1.0308 with zinc-nickel coating: model 4259.1XL in PN 6, model 4259XL in PN 10/16 and model 4259.6XL in PN 25/40. The flange side follows EN 1092-1 – bolt circle, number of holes and bolts of the mating flange are in the flange dimensional drawing PN 6–40; tightening torques per nominal size are given by Viega in the instructions for use (bolts 8.8, hardened washers). Sequence: first the flange joint, then the press joint.

Press, groove, flange or weld from DN 65?

From 2½ inch, Megapress S XL no longer competes with other press systems but with the classic methods of pipeline construction. Viega states, as a manufacturer claim, up to 80 % less assembly time compared with welding in the XL sizes – the largest share of that falls not on the joint itself but on what is dropped: fire watch, welding permit, gas-free certification, weld testing, draining the line. On the other side stand the grooved coupling (detachable, from DN 65 with expansion accommodation, pipe ends have to be grooved), the flange (detachable, the standard at valves) and the weld seam (metallurgical bond, unlimited in size and wall thickness, but hot work). Which method carries when is shown criterion by criterion by the comparison of joining methods; the page Megapress or welding walks through the decision with an example, and the cost comparison calculator calculates it with your own figures.

Availability at Zickwolff

The standard names dimensions. What is listed here, we carry – from stock or to order; how quickly a size is available we clarify on request. Megapress S in ⅜–2 inch and Megapress S XL in 2½–4 inch we source as a Viega contract dealer directly from the manufacturer – connectors, fittings, flange and threaded adapters. The thick-walled steel pipe to EN 10255 and EN 10220 to go with it we carry in stock, in the XL sizes also as seamless boiler tube in the wall thicknesses of plant construction.