Union fittings and shutoff valves should be installed on both sides of trap for ease of servicing and trap testing.

在疏水阀两侧应该安装连接装置和关断阀，以简化维修和疏水阀测试。

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Union fittings and shutoff valves should be installed on both sides of trap for ease of servicing and trap testing.

在疏水阀两侧应该安装连接装置和关断阀，以简化维修和疏水阀测试。

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