Hi Mary,
Pressure cooker guarantees usually only cover the major components from manufacturing defects. They don't cover seals, rubber components, or even, in most cases, mobile parts. They don't cover parts from breakage, only manufacturing defects. You will almost always discover a defect within a few months, so the fact that it has a 25year warranty or a one year warranty is pretty much irrelevent. Although there is one brand "Silampos" that also guarantees the Thermal "sandwich" Base of their cookware against
failure (separation of the thermal layers) for 25 years.
If you want to repair your pressure cooker, however, the Pressure Cooker Centre in Australia has a huge selection of brands and all their spare parts, including
Aeternum and Lagostina spare parts. They do ship worldwide.
Another extensive source of information about suppliers of replacement parts in the USA, can be found at
www.missvickie.com
Helen