What signifies that a fire extinguisher's discharge indicator port is indicating an issue?

When the yellow disc is missing from a fire extinguisher's discharge indicator port, it signifies that there is an issue with the extinguisher. The yellow disc serves as a visual indicator of the charge status of the extinguisher and alerts the user to potential problems. If the disc is absent, it typically means that the extinguisher has been discharged or is inoperable.

The other indicators may not provide a clear or direct indication of the extinguisher's operational status. For instance, a blinking green light may represent that the unit is functioning correctly, while an intact pin indicates that the extinguisher has not been activated. A loose handle could suggest a mechanical issue but doesn’t necessarily mean that the extinguisher is unserviceable. Thus, the absence of the yellow disc directly points to a need for attention and possibly service or replacement of the extinguisher.