MTS Series 505G2 SilentFlo Hydraulic Power Unit Model 505G2-11 - Manual (Page 47)

Adjusting the HPU Output Pressure Level
Model 505G2.07/.11 SilentFlo™ HPU 47
Adjusting the HPU Output Pressure Level
1. Turn on high hydraulic pressure. Ensure that there are no flow demands by
the system.
2. Loosen the nut securing the output pressure control.
3. Monitor the hydraulic pressure gage located on the control manifold. Adjust
the output pressure as follows until the desired pressure is displayed.
• Turn the output pressure control clockwise to increase the pressure.
• Turn the output pressure control counterclockwise to decrease the
pressure.
Note If this pressure level is to be used for longer than 10 minutes, proceed to
“Adjusting the auto-cooling level” procedure.
4. Hold the output pressure control to prevent it from moving and tighten the
nut to secure it.
5. Check the hydraulic pressure gage to ensure that the desired hydraulic
pressure is being maintained.
Adjusting the Auto-Cooling Level
The auto-cooling function is integrated into the control manifold. During periods
of low flow demand from the external hydraulic circuit, this feature provides two
important benefits: a re-circulating flow that ensures hydraulic fluid filtering
whenever the unit is on, and safeguarding against hydraulic fluid over-
temperature. It functions by opening a hydraulic flow path through the fluid
conditioning circuit when external hydraulic demand for flow is low. When the
external demand increases, this feature closes the path to provide the full flow of
the HPU to the external demand.
The effective operating range of the auto-cooling circuit is between system
pressures of 14 MPa (2000 psi) to 21 MPa (3000 psi). In order for the Auto-
Cooling Valve to function properly, it must be re-adjusted anytime the output
pressure will be changed for longer than 10 minutes.
Note If the test condition requires a maximum pressure level of less than 14
MPa (2000 psi), consult MTS.
An incorrect adjustment may cause one of two conditions:
• An over-temperature interlock as indicated by the front panel indicator. A
mis-adjustment of the Auto-Cooling Valve may prohibit the flow of
hydraulic fluid across the heat exchanger
• Unexpectedly reduced system performance. A mis-adjustment of the Auto-
Cooling Valve may reduce the full flow of the pump to the external circuit
The Auto-Cooling Valve is factory set for an output pressure setting of 21 MPa
(3,000 psi). If the HPU will be operated with a 0.2 MPa (25 psi) or larger
decrease (or increase from a lower set pressure) for a period exceeding 10
minutes, an adjustment to this valve will ensure that neither of these conditions
occurs. The Auto-Cooling Valve is located on the control manifold.