General Tools and Instruments NGD8800 - Manual (Page 9)

COMBUSTIBLE GAS DETECTOR
8
6-2 Automatic Ambient Reset Feature
This combustible gas detector features an Automatic
Ambient Reset function that sets the unit to ignore
ambient concentrations of combustible gas.
ƒ Automatic Ambient Setup - Upon initial power on,
the unit automatically sets itself (approx. 1.5 minutes)
to ignore the level of combustible gases present at
the tip. Only a level, or concentration, greater than
this will cause an alarm.
CAUTION!
This feature will cause the unit to ignore any
combustible gases present at power on. In other
words, with the unit OFF if you place the tip up to a
known leak and switch the unit on, NO leak will be
indicated!
ƒ Ambient Reset Feature - Resetting the unit during
operation performs a similar function; it programs the
circuit to ignore the level of combustible gases
present at the tip. This allows the user to 'home-in' on
the source of the leak (higher concentration). Similarly,
the unit can be moved to fresh air and reset for
maximum sensitivity. Resetting the unit with no
combustible gas present (fresh air) causes any level
above zero to be detected.