How to resolve the issue of slow operation in the Doosan DH220-V—a problem that becomes particularly pronounced when the machine is under load.
Inspection procedure: Doosan Diagnostic Tool UVIM Support Doosan Excavators High Quality 1. Check pilot pressure: The pilot pressure measured at the gear pump is 40 bar. 2. Check negative control pressure: The pressure is 40 bar with the control levers in the neutral position and drops to 7–8 bar during operation; this indicates that the valve spools are functioning correctly. Doosan DMS-5 Diagnostic Software with Troubleshooting v53.3.1 (07.2026) 3. Measure main pump pressures (front and rear): The relief pressure measured at the main pump test ports is 250 bar, and the system fails to boost pressure (normal relief pressure is 330 bar); this indicates abnormal pressure requiring adjustment. 4. Adjust the main relief valve: Tightening the 350-bar adjustment nut by one full turn resulted in no change in pressure; this indicates a fault in the main relief valve. 5. Remove, clean, and reassemble the main relief valve. Caus...