Thanks mike
First one with a blue pump head, bypassed the valve but there was too high an initial build up of pressure, and the pump started to struggle. This machine has a return to the tank and pre heat system through the inline heater to warm the tank before you clean.
By going direct to the outlet ( the female connector where the hose connects caused too much presure
) and by bypassing the presure relief valve and going through the bypass there wasnt enough pressure at the wand tip .
I know a lot of it probably makes no sense but I think the crooks of it is I need to replace the pressure regulator.
First time I have stripped one of these down.
John