MTS Series 505G2 SilentFlo Hydraulic Power Unit Model 505G2-11 - Manual (Page 49)

Adjusting the Auto-Cooling Level
Model 505G2.07/.11 SilentFlo™ HPU 49
5. After the final adjustment tighten the nut to secure the setting.
6. Hold the HPU Output Pressure Control to prevent it from turning while
tightening the nut.
7. Verify that the output pressure remained at the desired level and tighten the
nut to secure the setting.
A. Hold the Auto-Cooling Valve stem to prevent it from turning while
tightening the nut.
Adjusting the Auto-
Cooling Valve if the
HPU shuts down due
to an over-temperature
condition or if the HPU
fails to deliver the full
flow to the external
circuit.
Adjust the Auto-Cooling Valve if:
• The HPU shuts down due to an overtemperature condition that has been
determined to not be caused by a fault in the heat exchanger circuit or
• If the HPU fails to deliver the full flow of the HPU to the external circuit.
1. With the HPU running in high and the HPU set for the desired output
pressure, loosen the nut on the Auto-Cooling Valve located on the control
manifold.
2. Adjust the Auto-Cooling Valve setting by slowly turning the valve
clockwise. If the valve shifts, a sudden change in pitch will be heard from
the pump. Reversing the valve adjustment a number of times will aid in
identifying the proper setting. Make a final counter-clockwise adjustment.
An increase in pump pitch will be heard that corresponds with the opening
of the valve. Stop adjusting at this point. If no valve shift is audibly or
visually detected and the valve has been fully closed go to step 3.
Important Adjustment of the Auto-Cooling Valve to a level too close to the
desired output pressure may cause an unstable condition
characterized by rapid valve shifting. This condition will produce an
audible flutter and can be seen as an erratic movement of the
needle on the pressure gage.
Adjustment of the Auto-Cooling Valve at or above the desired
output pressure may prevent the valve from shifting and result in
the HPU overheating.
Adjustment of the Auto-Cooling Valve that results in the valve
shifting at a level substantially below the desired output pressure
may result in reduced flow to the system.
3. Adjust the Auto-Cooling Valve by slowly turning the valve counter
clockwise. When the valve shifts a sudden change in pitch will be heard
from the pump. Reversing the valve adjustment a number of times will aid
in identifying the proper setting. Make a final counter-clockwise
adjustment, an increase in pump pitch will be heard that corresponds with
the opening of the valve. Stop adjusting at this point.
4. Confirm the Auto-Cooling Valve setting by slowly cycling the HPU Output
Pressure Control. Decrease the HPU output pressure and note a decrease in
pump pitch when the valve closes. At the point when the valve closes the
pressure on the gage will momentarily hesitate during the adjustment.
Increase the pump output pressure to the desired pressure setting and note an
increase in pump pitch when the valve opens. Once again the pressure gage
will show a momentary hesitation when the valve opens.