Atlas Copco MAS 200, Instruction Book

Page: 85 / 94

7.6 Modulating control : Adjusting the set pressure of the control
valve
Before installation
modulating control
The following procedure can be used to adjust the set pressure of the control valve before
installation (with an accuracy of less than 0.5 bar) :
• Connect the control valve to a manometer and the bleed-off nozzle.
• Apply the desired set pressure to the inlet of the control valve.
• Lift the hand wheel and screw it as far clockwise as possible.
• Screw the hand wheel counterclockwise until the manometer indicates 1.5 bar(e). Click the
hand wheel down.
On a working machine
The following routine can be used to adjust the set pressure (half differential pressure lower than
the unloading pressure of the unit) of the control valve on a working machine.
• Stop the compressor.
• Set the load pressure on the Elektronikon to its minimal value. Set the unload pressure on
the Elektronikon to its maximum allowed value.
• Lift the hand wheel clockwise as far as possible without tightening it.
• Start the compressor.
• Throttle the outlet of the compressor until the outlet pressure is 10% higher than the desired
set pressure.
• Screw the hand wheel counterclockwise until the outlet pressure is 0.05 bar lower than the
desired set pressure. (Screwing the hand wheel clockwise will increase the desired set
pressure and thus increase the unit’s outlet pressure). Pushing the hand wheel back down
can lock the setting.
• The direction of turning the hand wheel should be maintained when the set pressure is
adjusted. If the direction is changed, compensation of hysteresis might be necessary in
order to avoid deviation from the desired value.
• After the first adjustment, the unit should run loaded for about 1 hour without changing the
outlet throttling, after which a slight readjustment might be necessary to let the outlet
pressure be 0.05 bar lower than the desired set pressure.
• Set the Elektronikon; see next chapter “Elektronikon settings”.
• If later on a slightly higher set pressure is desired, turn the hand wheel a little bit clockwise.
If a slightly lower set pressure is desired, turn the hand wheel a little bit counterclockwise.
Instruction book
APF219617 83