Abstract: A gas valve is disclosed with a housing (1), which has a gas pathway consisting of an inlet branch (2) and an outlet branch (3) and an insertion opening (4), which is accessible from the exterior and intersects the gas pathway, wherein the housing (1) affords two axially spaced housing sealing surfaces (6) extending around the insertion opening (4) and wherein the area of the insertion opening (4) between the two housing sealing surfaces (6) is laterally closed with the exception of the mouth of one of the two branches (2, 3) of the gas pathway whilst the other branch on the other side of this area is in communication with the insertion opening (4), and a cartridge (5), which is inserted into the insertion opening (4) and has two cartridge sealing surfaces (8) complementary to the housing sealing surfaces (6) and an interior, which is closed at at least one end, whereby the interior is laterally closed between the two cartridge sealing surfaces (8) and on the other side of at least one of the cartridge se