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Hydrostatic pump charge pressure adjustment.............5
Hydrostatic pump relief valve adjustment
The hydrostatic pump used to drive the conveyor chain on the feeder breaker has two main pressure relief valves and one charge relief valve (Fig. 73). The main relief valves are preset at 5,000 psi and the charge relief valve at 350 psi.
To adjust the main relief:
WARNING! Follow all standard safety procedures before beginning this adjustment process. Failure to do so may result in serious injury or death.
1. Locate the forward direction pressure port on the hydrostatic pump (Fig. 73) and remove the forward pressure hose from the pump. Plug the hose end and cap the pump fitting.
WARNING! The hose plug and the fitting cap must be properly torqued before proceeding as the system pressure will reach 5,000 psi. Failure to do so may result in serious injury or death.
2. Turn the machine on (refer to Start up section in this chapter).
IMPORTANT! Do not run the pump for a long period of time while setting the reliefs as all of the flow will be going over the relief. Excessive pump operation with the lines plugged will result in overheating and the eventual failure of the pump.
3. Two people are required to adjust pressure settings. One person must move the conveyor direction valve handle to the forward direction, monitor the pressure gauges, relay pressure gauge readings to the mechanic making the adjustments, and be ready to shutdown the machine via the panic bar, if necessary. The second person will perform the actual pressure adjustment at the hydrostatic pump (Fig. 73).
WARNING! Two people are required to adjust the pressure settings. One person must move the conveyor direction valve handle to the forward direction and remain at the conveyor controls and panic bar at all times during the adjustment procedure. Failure to do so may result in serious injury or death.
The conveyor forward pressure must be adjusted if the system pressure gauge does not read 5,000 psi when the conveyor direction valve is placed in the forward direction.
If the system pressure gauge does read 5,000 psi during the conveyor forward relief pressure test, then proceed to Step 8.
4. Locate the corresponding relief pressure adjustment valve for the forward pressure port (Fig. 73). ______________________________________________________________
5. Loosen the hex jam nut by turning counterclockwise.
6. Insert an internal hex key into the pressure adjustment screw and turn the internal hex key clockwise to increase the conveyor relief pressure setting and counterclockwise to decrease the conveyor relief pressure setting.
CAUTION! Do not turn the adjustment screw in any further once it is felt that the screw has bottomed out as this may damage the needle valve and seat. Likewise, do not turn the adjustment screw out all the way as this may present difficulties in reassembly and may introduce contamination into the hydraulic pump.
NOTICE! While adjusting the relief pressure, if the system pressure gauge reading is not changing, it must be determined that the conveyor direction valve handle is in the correct position and that the corresponding pump pressure port hose was disconnected and plugged. To resolve this issue, place the conveyor direction valve handle in the opposite direction.
7. Monitor the system pressure gauge until the desired 5,000 psi pressure relief setting is obtained for the conveyor pressure.
8. Lock the pressure adjustment screw in place by turning the hex jam nut clockwise while still holding the pressure adjustment screw with the internal hex key so as not to alter the desired pressure setting. Once the hex jam nut is snugged down, observe the system pressure gauge to ensure the relief pressure setting was not accidentally changed during the tightening of the hex jam nut. If the relief pressure setting has changed, loosen the hex jam nut and readjust the pressure to 5,000 psi with the adjustment screw.
9. Return the conveyor direction valve handle to the neutral position and turn the machine off.
10. Cautiously remove the hose plug and fitting cap from the conveyor pressure hose and the pump pressure port. Adhere to all safety procedures when performing this step. Install the pressure hose to the pressure port on the pump.
WARNING! The hose fitting must be properly torqued before proceeding as the system pressure will reach 5,000 psi. Failure to do so may result in serious injury or death.
11. Return to Step 1 and repeat the adjustment procedure for the conveyor reverse pressure relief setting.
12. Restart the machine and check for leaks at the pressure ports of the hydrostatic pump by positioning the conveyor direction control valve in both forward and reverse direction.
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Hydrostatic pump charge pressure adjustment
WARNING! Follow all standard safety procedures before beginning this adjustment process. Failure to do so may result in serious injury or death.
1. Start the machine (see Start-up procedure in this chapter).
2. The charge pressure gauge (Fig. 75) should read 350 psi while the machine is at idle, the conveyor direction valve handle is in neutral, and the oil temperature is between 90°F and 110°F. Locate the charge pressure adjustment screw (Fig. 73).
Note: The charge pressure will drop slightly (as low as 290 psi) while the conveyor is running. This is normal and does not require further adjustment after initial setting.
Note: The charge pressure will vary depending on oil temperature (the hotter the oil, the lower the pressure and the cooler the oil, the higher the pressure). This is normal and does not require further adjustment after initial setting.
3. Insert an internal hex key into the pressure adjustment screw and turn the internal hex key clockwise to increase the charge pressure setting and counterclockwise to decrease the charge pressure setting.
CAUTION! Do not turn the adjustment screw in any further once it is felt that the screw has bottomed out as this may damage the needle valve and seat. Likewise, do not turn the adjustment screw out all the way as this may present difficulties in reassembly and may introduce contamination into the hydraulic pump.
4. Monitor the charge pressure gauge until the desired 350 psi pressure setting is obtained for the charge pressure.
5. Lock the pressure adjustment screw in place by turning the hex jam nut clockwise while still holding the pressure adjustment screw with the internal hex key so as not to alter the desired pressure setting. Once the hex jam nut is snugged down, observe the charge pressure gauge to ensure the relief pressure setting was not accidentally changed during the tightening of the hex jam nut. If the charge pressure setting has changed, loosen the hex jam nut and readjust the pressure adjustment screw.
6. Turn off the machine.
