GMI GT series - Page 63

7-3
CO (CARBON MONOXIDE MODE)USER HANDBOOK
7.4.1 CO Direct
In this option, normal
atmospheric air is checked for
CO content.
The typical display for this
mode is shown in Fig. 7.3:
7.4.2 Differential CO
This option enables the user to zero out ambient CO backgrounds and
display the differential measurement. This is useful in areas where
the ambient CO is high from other sources such as trafc pollution.
Note: It is possible to have negative readings on the display in this
mode.
The typical display for this
option is shown opposite, in
Fig. 7.4
To zero the displayed CO reading:
• Press and hold ZERO .
7.4.3 Air-Free CO
Air-free CO is the CO reading modied by the O
2
reading, therefore
this measurement will only be available when an O
2
sensor is tted.
The purpose is to determine whether or not the emissions from an un-
ventilated appliance, principally an oven or a stove / cooker, are safe.
Fig. 7.4 Differential CO
Fig. 7.3 CO Direct