Gaggia EVOLUTION E90 Mode D'emploi Et D'entretien page 64

English
Lack of volumetric counter impulses.
On starting a volumetric control coffee cycle, the correct function of the
volumetric counter is checked by the reading of the number of impulses
sent by the same to the micro-controller.
Should no impulses by recorded for a period exceeding 5 seconds the
LED relative to the selected measure begins flashing (ie. the led relative to
key T4).
After one minute in which no impulses are recorded (volumetric
counter time out), the measure underway is automatically stopped.
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