Heath Consultants GT Series - Manual (Page 50)

4-8
USER HANDBOOK
Fig. 4.8 Ticker (Geiger) Threshold
4.5.3 Range Selection
The instrument initially selects the PPM range which
autoranges to LEL/VOL.
Note: When CO range is selected the display reverts to
the 2-gas display.
4.5.4 Lights
To switch ON the backlight:
• Press and hold the Centre button .
To switch ON the flashlight:
• Press and hold the Centre button again.
The backlight and flashlight are both timed to switch OFF
after two minutes. Both can be switched OFF by a third
press and hold the Centre button .