Water Pump Accumulator Setting

Shuflo 4008 uses an Internal Bypass to control pump cycling
Bypass begins opening at 40# and is fully open at 62#
Pump Pressure Switch STOP set point is 55# ---Start set point is 40#

If full by-pass is reached before the shut-off setting, the pump will not shut off. Shurflo 4008 Manual


4008 Bypass/Pressure Switch Adjustment Procedure

Did you try adjusting the cutoff switch on the pump?

The pressure setting on an accumulator tank should be just barely above the cut-on pressure of the pump. That way the accumulator tank will empty before the pump cuts on.

However, the accumulator tank setting can not be why your pump won't shut off. When the tank gets full, the pressure will go up to shut off the pump regardless of any settings.

Now, if you are actually talking about the bypass setting on the pump, disregard my post. My post only applies to actual accumulator tanks.

If the pump bypass setting is set too low, the pump will never turn off.