这被称为排出压力。
This is referred to as head pressure.
youdao
将系统中的水排出，直到锅炉压力读数降为零。
Draw off system water until boiler pressure reads zero.
压力一排出去，这个装配就可以被准备使用了。
The assembly was ready for use as soon as the pressure had vented.
应用推荐
模块上移
模块下移
不移动