ST-45 PUMP — MAINTENANCE (PUMP)
ST45 PRESSURE SETTING SEQUENCE
To set maximum pump pressure:
1.With the engine turned “OFF”, loosen the ¼” hydraulic hose attached to the compensator valve located on the top of the Main Delta Q Pump.
Figure 44. Compensator Valve
2.Loosen the jam nut located on the end of the compensator valve (Figure 44).
3.Turn the compensator adjustment nut (Figure 44) clockwise until tight. Tighten the ¼” hose leading to the compensator.
4.Start the engine and loosen the jam nut located on the maximum relief valve cartridge (Figure 45).
5.Run the engine at maximum RPM (2550) and turn the volume control knob
MAXIMUM RELIEF
VALVE CARTRIDGE
JAM NUT
MAIN
RELIEF VALVE
VOLUME 
CONTROL
Figure 45. Hydraulic Drive Pump Manifold
6.On the electrical control panel, turn the pump control switch (Figure 22) and the test switch (Figure 31) to the “ON” position. Using an allen wrench, adjust the main relief valve (Figure 45) to 3500 PSI.The reading can be taken from the pumping pressure gauge (Figure 46).
7.Hold the main relief valve adjusting bolt with a wrench and tighten the jam nut. Using the test switch, double check the pressure reading to make sure the setting has not changed.
Figure 46. Pumping Pressure Gauge
8.Turn the engine off and loosen the hose from the compensator valve. Loosen the jam nut and turn the compensator adjustment nut (Figure 44) counter- clockwise ½ turn. Tighten the ¼” hydraulic hose.
9.Start engine and run at maximum RPM with volume control at maximum volume (fully
MAYCO
