A regulator can hold the correct static value yet fail during rapid flow. Droop lowers pressure under demand, creep raises downstream pressure after flow stops, and hunting creates repeated oscillation. Each behavior changes bubble height, forming force, or eject intensity.
The downstream pressure trace should be compared with flow demand and upstream supply. A regulator that is undersized, contaminated, installed backward, operated near its control limit, or paired with an unsuitable pilot volume may respond poorly. A blocked relief path can make pressure decay too slowly between sequence steps.
The regulator should be selected for the required flow range and dynamic response, then installed with adequate upstream pressure and clean air. Control settings should not be tuned around a regulator fault. After service, the complete cycle trace must be checked rather than only the setpoint at rest.