TL;DR

Short cycling means demand is catching up with the receiver too fast. Find and fix system leaks first. If leaks are minimal, the receiver may be undersized for the demand pattern.

What you might see

compressor starts and stops every few minutes
receiver pressure oscillates rapidly
high start count in Elektronikon log
pressure drops quickly after each stop

Likely causes

Tap to mark as ruled out

System air leak allowing pressure to decay faster than the VSD can modulate the compressor output
Receiver tank undersized for the application, providing insufficient buffer volume
Pressure band set too narrow, causing the compressor to start/stop instead of modulating speed
High base demand from an open blow-off or partially open drain valve

Required tools

Sonic leak detector
Soapy water spray bottle
Elektronikon controller (start count log access)
Pressure gauge
LOTO kit

Safety first

Do not open any system connection while the receiver is pressurized. Isolate and depressurize the section being worked on.
Lock out the compressor before adjusting controller pressure bands if access requires opening the control panel.

Procedure

7 steps · ~45 min

1
Record the Elektronikon start count log. More than 6 starts per hour indicates a short-cycling condition.[1]
2
Shut down the compressor and pressurize the system to normal operating pressure. Monitor the system pressure with all demand isolated. A decay of more than 0.1 bar per minute indicates significant leakage.
3
Walk the distribution system with a sonic leak detector or soapy water at every fitting, quick-connect, valve, and drain point. Tag all leaks for repair.
4
Check all automatic drain valves. A stuck-open drain valve can cause continuous pressure loss.
5
Widen the cut-in to cut-out pressure band in the Elektronikon controller if leaks are minimal. A wider band allows the VSD to modulate more before stopping.[1]
6
Calculate the required receiver volume for the application load cycle. A rule of thumb is 0.5 liters of receiver per CFM of installed compressor capacity as a minimum.
7
Repair all tagged leaks and retest. Short cycling should resolve once leakage is below 10% of compressor free air delivery.

Sources

Atlas Copco GA VSD+ Air Compressor User Manual, Atlas Copco
Atlas Copco GA VSD+ IOM, system leakage and pressure band configuration procedures (general)
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