VIEGA Smartpress Coupling 20 x 20 mm, Stainless Steel, Press x Press, Art. 729769

The coupling is made for 20 mm pipe from the Viega Smartpress, Pexfit Pro or Pexfit Fosta systems, and each end must take one of these pipes. Viega states that Smartpress connectors were not tested with other makers' pipes, so proper function cannot be ensured in that combination.

In both drinking-water and heating installations, Viega limits the Smartpress operating pressure to a maximum of 10 bar. The temperature limit depends on the type of installation: up to 70 °C in drinking-water lines and up to 80 °C in heating lines. For any other area of use, or when in doubt about the material, Viega asks to be contacted first.

It is a safety mechanism in Viega's press connectors, not a standard. Until the 20 mm joint has been pressed it stays deliberately leaky, so a missed pressing is found by the leak test on the finished, still uncovered installation. Viega gives the detection range as 1–6.5 bar with water and 22 mbar–3 bar with air.