NR502 Non-Return Valves is used in the installation of pressurised water heaters. They prevent the backflow of water from a water heater to the mains line. This serves the dual purpose of protecting the mains supply from contamination, and the loss of water that has already been heated. Maximum temperature: 40° C Maximum inlet pressure: 1400 kPa 15mm BSP (F) MATERIALS:: Body - Cast gunmetal Internal Parts - Brass and stainless steel Seat Disc - Nitrile