Adjusting Group Pressure

[chas]

It's been interested researching the Mini as I write a new manual for it to see how LaSpaz adapted the V2 in order to convert it to a vibe pump. The group pressure adjustment is very interesting. At first I thought that the expansion valve was omitted in the Mini design. However, they actually repurposed it as the group pressure adjuster.

On the V2, you twist the bottom of the valve to adjust it to just open at 12.5 bar as a protection mechanism. When it opens the water dumps into the drain tray. On the Mini, the valve is positioned more to the left and slightly behind the pressure gauge. The bottom of it has a hose that runs back to the inlet of the vibe pump. So you adjust the expansion valve with a blind basket or rubber disk in the PF basket to open at the desired group pressure. The valve then prevents the group pressure from exceeding this amount by routing water back the the pump inlet.

Mini Group Pressure Adjustment

Expansion Valve2.jpg (70.52 KiB) Viewed 4113 times

Written instructions from Jason at CC:

1) Remove the front splash panel (2 screws)
2) You can see the valve behind the gauge, sometimes they can be turned by hand or use an adjustable wrench. Since it is a vibratory pump the expansion valves regulates the pump pressure.
3) Turning to the right increases pressure, left to decrease.
4) Always measure the pressure on the group pressure gauge while using a blank.