Close shutoff No. 1. Slowly loosen hose connection at TC# 2 until differential gauge rises to about 2 PSI then tighten. If the differential reading does not decrease record check valve as tight.

• 关闭1号关闭阀。慢慢松开连接在测试旋塞2号上的软管直到压差表上升到大约2PSI，然后紧固。如果压差读数没有降低，则记录止回阀为密封紧密。