采用大小适中的扳手，松开止回阀盖。旋下止回阀盖螺丝并拿起。

Using an appropriate sized wrench, loosen the check valve cover. Unscrew the check valve cover and lift off.

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测试端口应该内置止回阀并配置阀盖。

Test ports shall have internal check valve and be equipped with caps.

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采用尺寸大小适中的扳手松开止回阀阀盖。宁松止回阀阀盖并将其取出来。

Using an appropriate sized wrench, loosen the check valve cover. Unscrew the check valve cover and lift it off.

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