Note : Vacuum relief valves are not designed or approved as back-siphonage backflow preventers. For protection against back-siphonage install Watts Series 288A vacuum breakers.

• 注意：蒸汽安全阀不适用于、也不被认可用作倒虹吸防倒流装置。如果需要对于倒虹吸现象提供保护，则需要安装美国瓦茨系列288A真空断路阀。