Something I thought I would put out there, for your delectation. There is a reason the group seals on a Evo will last as long as they do, which can be 2+ years in a commercial environment and longer domestically.
In a typical HX" Bosco" style lever group, the 3 seals act as a water inlet valve and the lower one makes the pressure. the lower 2 seals pass the inlet port/s and get nibbled, especially the lowest one which splays out under pressure.. Finally the top two seals are always extra hot as the very hot 124+C boiler water is constantly circulating and of course enters the chamber past (and under) the pressure seal during the initial pull down. This heat and lubricant washout adds more reasons for the relatively short life of their seals.
In contrast the LSM group as used by ACS and Nurri, both never have water washing lubricant from the seals, the seals never pass the port and they never get exposed to the super high temps of the others because of gentle active group heating.
Just in case people were not fully aware of whyâŚunless you had a faulty seal , that no one will have had to replace them due to wear since the Evo launched.
