If it does not drop but there is a small leakage at test cock No. 2, then No. 1 ball valve has a small leak, but No. 1 check valve is tight.
英
美
- 如果水柱没有下降,但是测试旋塞2号有点泄漏,则1号球阀有点泄漏,但是1号止回阀密封紧密。