MTS Hydraulic Power Unit Model 506-92 - Manual (Page 22)

3-10 Service
Refer to Figure 3-2 for the location of the components indicated in the
following procedure.
1. Turn off the HPU.
2. Make sure that the output pressure gage reads zero (Figure 3-2 shows
the location of the pressure gage).
3. Remove the plastic cap on both pump pressure controls. Loosen the
locknuts and turn both pressure controls fully counterclockwise.
4. Loosen the locknut on the back-up relief valve and turn the
adjustment knob fully counterclockwise.
locknut
adjustment knob
VW-G050
5. Press Pump 1 Select on the HPU Control Panel.
6. Press Start to run the HPU at low pressure, then press High Pressure.
7. Observe the pressure gage and alternately turn the back-up relief
valve adjustment and the pressure control on pump 1 clockwise
(Adjustment increments should be approximately 500 psi (3.45 MPa)
apart as indicated on the pressure gage.).
Stop adjusting at approximately 500 psi (3.45 MPa) above the desired
output pressure (typically 3000 psi/21 MPa).
8. Tighten the locknut on the back-up relief valve.
9. Turn the pressure control on pump 1 counterclockwise until the
desired output pressure is reached.
10. Turn off the HPU.
3 . 2 . 1 Output Pressure Adjustment