Multiquip ST-45HRM ST-45 Pump -TROUBLESHOOTING Hydraulic System, Hydraulic System Troubleshooting

ST-45 PUMP —TROUBLESHOOTING (HYDRAULIC SYSTEM)

Practically all breakdowns can be prevented by proper handling and maintenance inspections, but in the event of a breakdown, please take a remedial action following the diagnosis based on the Hydraulic System Troubleshooting (Table 10) information shown below and on the proceeding page. If the problem cannot be remedied, please leave the unit just as it is and consult our company's business office or service plant.

TABLE 10. HYDRAULIC SYSTEM TROUBLESHOOTING

SYMPTOM	POSSIBLE PROBLEM	SOLUTION
		Check TB1 terminal #17. If this terminal is energized when the
	Delta "Q" compensator not de-energized	pump is turned on, the pump will not cycle because the
	when pump is energized?	compensator is dumping controll pressure to the accumulator tank.
		Check K-3 relay and replace if necessary.
	Volume control not turned open?	Turm volume control valve counter-clockwise to open.
No hydraulic oil flow from axial piston
pump.	Hydraulic oil level low?	Fill resevouir to proper level.
	Restricted suction screen?	Clean suction screen.
	Main pressure relief valve open	Remove cartridge. Clean and reset. Replace cartridge if
		ncessisary.
		This emergency cycle switch, located in the control box, can be
	Proximity switch is not sending a signal?	used to determine which switch is faulty. Determine malfunctioning
		proximity switch and replace.
		Turn on pump switch. Check TB1 terminal #35 and #36 to
	Pilot cycle valve malfunction?	determine if current is flowing to valve. Check detents in valve for
Drive cylinders will not cycle		proper operation.
	K-4 relay faulty?	Check the proximity switch enclosure.
	Main cycle valve(manifold) faulty?	Check spool or centering springs. Replace or repair as necessary.
Accumulator pressure drops to zero	Low nitrogen charge in accumulator	Re-charge accumulator bladder with nitrogen to 1100 PSI.
on every cycle	bladder?
Accumulator pressure is below 1750	Unloading valve setting too low?	Adjust unloading valve until 1750 PSI is reached.
PSI.
Accumulator pressure is not	Cartridge at port 4-D on manifold block	Check solinoid and cartridge. Replace if necessary
discharging when switch is turned off	is not working?

PAGE 62 — MAYCO ST-45HRM PUMP — OPERATION & PARTS MANUAL — REV. #4 (07/16/04)