Been dabbling away,have the 123456789abcdef etc., i have to run at a or above or the pump will start cutting out and cycling below this and not hold steady flow.Now when i go above a (its cycling at this setting with flow stopped),the cycling gets steadily more aggressive until at d with the flow stopped the pump doesn`t actually stop and the water can be heard agitating inside the pump,i reckon its releasing the water backwards to ease the pressure,at this setting , its got to be able to do something else it would just burn out. This setup i have has two digi-controllers so i have switched them over with identical results. So i am set at "a" with 70m of 6mm microbore,flow rate of my choosing 1 to 9 and its all hunky dory except the pump wont ever stay off for more than 2-3 secs with the flow stopped.
I am hoping the fact that the pump will run continuous at a higher pressure setting with flow off is a clue and maybe someone is going to tell me i have a dodgy diaphragm seal or similar unless i am missing the know how to adjust the cut off sensitivity that someone mentioned.