VMAC - Vehicle Mounted Air Compressors
VMAC Technical Support: 888-241-2289
VMAC Knowledge Base: www.kb.vmacair.com
45
Performance Testing and
System Adjustments
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Install the VMAC test tool at the AOST outlet with the 70 cfm (0.190 in) orifice.
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Ensure that the ball valve is closed.
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Place the transmission in “PARK” and fully apply the park brake.
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Allow the engine to run until it is at operating temperature.
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Turn on the air compressor system and allow it to operate until the oil is warm.
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Observe the pressure gauge. Pressure should be approximately 150 psi.
Open the ball valve on the test tool and observe the engine tachometer*:
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*Engine speed should increase to approximately 2,400 rpm.
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Close the air valve slowly to allow the system pressure to rise.
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Once system pressure is at maximum, slowly open the ball valve on the test tool
until the pressure on the gauge begins to drop. Engine speed should ramp when
the pressure drops to approximately 140 psi.
Performance Testing and System Adjustment
System operation can be tested using the tools that will be operated by the system
or by using the VMAC Test Tool (A700052) with the 70 cfm (0.190 in) orifice in the
outlet to simulate tool use (Figure 46).
Disconnect all downstream equipment (hose reels, etc.) and connect
the test tool directly to the discharge fitting on the AOST.
Ensure there are no leaks in the test tool. The system may not idle
down if there are leaks in the lines or fittings.
Figure 46 — A700052 VMAC Air Test Tool
Install orifice here
Orifice
Ball valve
JIC Adapters
