Check ring (IEC 60073):
To do
Action pending
Verified
Scan + photo only
Failed / alarm
Faded = not in line-up
Pipes (ISO 14726): main colour along the pipe, identification band in the middle (see the drawing legend)
Valve body: solid = closed, hollow = open, flashing = moving, dashed = no sensor
Tank levels: LAH high-level and LAL low-level alarm lines; the pump stops automatically at either (demo limits)