you say the neutral point and before the suction.
Read my post again....
Also the pressure relief valve is on top of my tank
This is what I mean about terminology. If you are referring to the red thing in the first picture, that is the expansion vessel., not a tank. And it is not a pressure relief valve. That is to the right of the boiler
I answer my questions such that you are guided to learn the right answer rather than spoon feeding.