MTS Hydraulic Power Unit Model 506-92 - Manual (Page 26)

3-14 Service
3.2.4 Main Pump Low-Inlet Pressure Switch Adjustment
The main pump low-inlet-pressure switch shown in the figure below
monitors the pressure level supplied by the supercharge pump at the input
to the main pumps. The switch protects the main pumps by turning off the
HPU if the supercharge pump pressure drops below the minimum level
required by the main pumps.
VW-G052
adjustment knob
Pressure Switch –
Cover Off
The switch is set at the factory to activate at 30 psi (0.21 MPa). This switch
may be adjusted with or without the HPU running.
When to adjust the
switch Figure 3-3 shows the location of the switch on the HPU. Check the
position of the pressure setting indicator on the switch (see the figure
above and left). It should be set at 30 psi (0.21 MPa). If it is not, follow the
procedure below to adjust the switch.
How to adjust the
switch Turn the adjustment knob located on top of the switch either clockwise to
increase the pressure setting or counterclockwise to decrease the pressure
setting to 30 psi (0.21 MPa).