used a shurflo 100 psi pump with an old type varistream for around 5 yrs now ,
always used to adjust blue dial in winter , as it would shut pump down sooner and there is a delay in water coming through when turning flow back on,
its down to the different temp. affecting my micro bore , it expands more in summer so pump takes longer to shut off , and water gushes out when you turn flow back on ,
on the same setting in winter the micro does not expand as much , so pump shuts of sooner, i don't bother to adjust it any more.
daz