LARGE HYDRAULIC OIL PUMP EFFICIENCY READING CONTINUED
11. Ensure load valve (Figure 21, Item 2) is fully closed by turning clockwise.
12. Start and run engine at 2,000 rpm (TM 5-2420-231-10).
13. Press POWER button (Figure 21, Item 5) to activate flow gauge (digital readout) (Figure 21, Item 4).
14. Raise loader and hold in raised (dead head) position (TM 5-2420-231-10).
Ensure jam nut is contacting base of load valve knob.
During adjustment, load valve knob may feel loose.
Maintain 2,000 rpm throughout test.
15. Fully open load valve (Figure 21, Item 2) on flowmeter (Figure 21, Item 3) by turning counterclockwise. Record
flow rate on flowmeter checksheet (3a).
16. Continue to run engine at 2,000 rpm while holding loader in dead head position. Slowly rotate load valve
(Figure 21, Item 2) until pressure gauge (Figure 21, Item 1) reads 2,000 psi (13,790 kPa). Read flow gauge
(digital readout) (Figure 21, Item 4) and record reading on flowmeter checksheet (3b).
17. Decrease engine speed to idle (TM 5-2420-231-10).
18. Lower bucket to ground and turn off machine (TM 5-2420-231-10).
19. On flowmeter checksheet under Pump Efficiency Calculation, divide flow reading (3b) by flow reading (3a).
This answer multiplied by 100 is the percent efficiency of the large pump.
Figure 21. Flowmeter.
END OF TASK