MTS Series 505 SilentFlo Hydraulic Power Unit Model 505-30 - Manual (Page 47)

Adjusting the Auto-Cooling Level
Model 505.20 - 505.30 SilentFlo™ HPU Operation 47
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.
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 in 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.
• Safeguarding against hydraulic fluid overtemperature.
This function works 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 overtemperature 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.