water therethrough barrel 68 has a portion 78 of reduced diameter on the inside of the barrel there is a relief valve seat 80 formed at the top of the portion of reduced diameter 78 on the exterior of the barrel there is a small groove 82 which contains a seal ring 84 which closes upon valve body seat 22 when the flush valve is in the closed position of the drawing the barrel may have a plurality of axially extending flow control slots 86 if desired positioned within barrel 68 is a relief valve 88 which has a stem portion 90 positioned for contact by actuating rod 48 the enlarged body 92 of the relief valve has an outwardly extending support lip 94 which has a lower surface thereof positioned upon barrel relief valve seat 80 when the flush valve is in the closed position of the drawing further details of the relief valve and its operation are described in the above mentioned copending application a tubular tailpiece 100 is connected to flush valve inlet 12 on one side and is connected to a check stop 102 at the other end the tubular tailpiece includes an inwardly directed annular curved recess 104 within which is positioned a seal ring 106 the seal ring is sealingly engaged with both the tubular tailpiece and the inner wall 108 of flush valve inlet 12 flush valve inlet 12 has an arcuate seating surface 110 which bears against the slanted wall 112 of the tubular tailpiece the slanted wall joins the inwardly extending annular recess with an outwardly extending annular projection 114 which limits the extent to which the tubular tailpiece can be inserted into the flush valve in order to secure the.