Tech Support Call


The Technical Support and Training team shares troubleshooting tips for a common air compressor issue, along with helpful hints for proactive troubleshooting with this service call scenario. This scenario is a compilation of calls and is not intended to reflect an actual situation or identify real people.

Jim is a service technician at XYZ Rentals. He is working on a Doosan XP825 air compressor that is building pressure during startup and bogging down the engine. Unable to diagnose the issue on his own, Jim calls the Doosan Dealer Technical Support and Training hotline – 1-800-633-5206 – for assistance. Jim provides the model year, model name and serial number listed on the aluminum plate near the controls of the air compressor. He also reads off the hour meter located on the control panel. The machine is not displaying any error codes on the controller screen so Jim is asked a few questions to help identify the issue.
Do you feel air coming out the Service Port at the bottom rear of the Air Inlet Unloader Valve?

The Air Inlet Unloader Valve is located on top of the airend. The Unloader Valve throttles the air into the airend. When the Unloader Valve is closed (doesn’t allow air into the Airend) the system is considered “unloaded.” The Service Port is located at the back of the Air Inlet Unloader just above the base. The Service Port is open to the displacement compensation chamber of the Unloader Valve diaphragm. If the diaphragm is perforated, regulated air will pass through the Service Port. Air blowing from the Service Port during operation indicates a damaged or worn diaphragm.

Jim checks the Service Port and does feel air blowing from the area. He must replace the part and uses the Online Parts Book to identify and order the correct part number for the XP825 air compressor. Once the part has been received, Jim should consult the Doosan air compressor manual for the proper replacement instructions of the Unloader diaphragm along with specific bolt torque specifications.

Helpful Hints for Proactive Troubleshooting

Manufacturer knows best
Who knows a machine better than the manufacturer? So when an issue occurs, first consult the Operations and Maintenance Manual, Parts Manual and Electronic Service Manual for troubleshooting information. Manuals can be accessed using Techpubs and parts can be identified through the Online Parts Book. The machine serial code is needed to find the correct manuals. The serial code is the last three characters of the full serial number shown on the machine data plate.

Proactive training
Doosan Basic Compressor Service instructor-led training covers this topic of troubleshooting and replacement along with other common air compressor issues in detail. If Jim has attended training, he could have saved time diagnosing the machine issue, resulting in quicker resolution and faster return to the customer or the rental fleet. The next session of Doosan Basic Compressor Service instructor-led training is scheduled for July 24 – 28 in Statesville, North Carolina. Log into Doosan Portable Power University website through PASSPORT for additional course details and online registration information.