The inlet pipe on my geyzer has a tee junction, one side goes into the geyzer the other ends with a green stop on the top of it. Problem is this is leaking.(the green stop on the top of the pipe) How do I make sure that when I switch off the water and remove this there will be no pressure in the geyzer and flood the house. What is this green stop for, doesn't look leke a pressure release. Why is it leaking, what possibly caused this?

We don't have them over here. Do you have a brand name for your geyser? Is it gas or electric? Tell me more about this green stop. Is it a hose bit with threads on the spout. We need more details and a picture would really be nice. Regards, Tom