Regal 3300 Owner's Manual page 173

The display panel at the helm features 3 windows. The left window
is a green power on indicator. The right window is and opening for
the Var-a-Brite light intensity detector. The center window is the red
warning indicator.
To check for fumes, turn the ignition key to the "on" position. the
green power on LED will show on and the red warning LED may light
momentarily to indicate a warm-up period for the sensor. The alarm
horn will not sound during this period.
If a vapor build-up reaches 10-20% of lower explosion limit the red
warning LED will light indicating a detection of fumes. Should this
condition last for longer than 10 seconds, the alarm horn will sound.
The alarm will continue as long as vapors are present. The alarm horn
may be silenced by pressing the "mute" switch, the the Red warning
light will remain on until the vapor problem has been resolved.
N OTT: The problem should never be considered corrected until
red warning light is out.
If the red LED begins to glow softly and or intermittently, it is an
indication that the gasoline vapor build-up is beginning to occur and
you can anticipate a full alarm momentarily.
Immediately have all passengers and crew exit the passenger
compartment. If an explosion or fire should occur, the probability of
injury will be greatly reduced if no one is in a confined area of the vessel.
In the event of an alarm:
N OTT: It is important to understand that an alarm would not
occur unless a problem existed. Carefully check all fuel
lines, gas lines, and any other potential sources of gas
leaks.
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