ok thanks very much. We will try to the test what you suggested. I will do with my plumberish friend. Dnt think he will flood my house or elecricute us.
I completely understand what you mean which is Just need to get rid of the valve temporary to let hot water through cylinder coil.
Let you know sooner or letter.
Many thanks
Your Plumberish Friend ? that says it all ! by that I take it he's done a few minor plumbing jobs at home ! and now he knows all about it, and your going to let him loose on your house ?? Good Luck