MTS Series 505G2 SilentFlo Hydraulic Power Unit Model 505G2-11 - Manual (Page 66)

Model 505G2.07/.11 SilentFlo™ HPU 66
Precharging the Surge Suppressor Accumulator
1. Ensure that system hydraulic pressure has been reduced to zero before
proceeding. To do this, turn off the hydraulic power unit and exercise the
actuator until it stops moving.
2. Remove the electrical power to the HPU via a circuit breaker at the power
source.
3. Open the top cover of the HPU. Use a 8-mm (5/16-inch) allen wrench to
unlatch the cover.
4. Remove the filler cap and reservoir cover.
5. Remove the hydraulic fluid.
Use the transfer pump to remove the old hydraulic fluid out of the reservoir
and into an appropriate container. Open the fluid drain to remove any
remaining fluid.
Note Every part to be installed must be cleaned and wiped dry.
6. Remove the hose from the pump output port to the bottom of the control
manifold.
7. Install the elbow (and reducer for the 505.11) to the surge suppressor
cylinder. Torque the fixtures to 33.9 N•m (25 lbf-ft).
8. Remove manifold from the reservior.
9. Install fittings inot the manifold inlet port.
10. Install the surge suppressor assembly into the manifold inlet port.
11. Reinstall the hose between the surge suppressor assembly and the pump
outlet.
12. Install the remote charging line and bulhead fitting.
13. Precharge the surge suppressor.
14. Add new hydraulic fluid to the reservoir.
Pump hydraulic fluid (filtered to 10 microns) into the reservoir. Stop when
the fluid level is full. Reinstall the strainer assembly of the filter cap.
Change the filter.
15. Run the HPU and check for leaks.
A. Press the Start switch.
B. Run the HPU at low pressure for about three hours to filter the new
hydraulic fluid.
C. Run the HPU in high pressure to check for leaks.
D. Press the Stop button.
Precharging the Surge Suppressor Accumulator
It is normal for a small amount of surge suppressor precharge loss to occur during
operation. Because of this gradual reduction in precharge pressure, the pressure
should be checked and recharged (if necessary) at regular intervals.