CAUTION: Do not install with strainer when backflow preventer is used on seldom-used water lines which are called upon during emergencies, such as fire sprinkler lines, etc.

• 警告:对于只在紧急状况下使用,平时很少有水流动的系统,如消防喷淋管道系统等等上的防回流阀,不要安装过滤器。