注：北方地区可根据当地防冻层深度增加地下埋管。

PS: Underground burying tube should be increased depending on local depth of anti-frozen in north area.

youdao

注：北方地区可根据当地防冻层深度增加地下埋管。

PS: Underground burying tube should be increased depending on local depth of anti-frozen in north area.

youdao