13-5
OPERATOR MAINTENANCEUSER HANDBOOK
13.2.3 Chemical Filter (Accessory)
The Chemical Filter assembly (Part No.67142) is available as an
accessory and the lter contents can be replaced with either of the
following:
(a) Colour indicated water absorbent silica gel.
The silica gel, supplied in a bottle, (Part No. 67205), provides
the user with a simple visual indication of lter gel saturation
by changing colour from gold to green when gel replacement
is required.
or
(b) NOx absorber, for absorbing Nitric Oxide (NO) and Nitrogen
Dioxide (NO
2
) from the sample.
The absorber, supplied in a bottle, (Part No. 67270), provides
the user with a simple visual indication of lter absorbent
saturation by changing colour from dark purple to brown
when absorber replacement is required.
The lter contents replacement procedure is the same, regardless
of chemical type.
CAUTION: The contents of this filter must only be
replenished with GMI approved chemicals.
Note: When replacing the chemical lter, it is essential to also
replace the dust lter.
1) Remove then discard the dust lter, as detailed in section
13.2.1 paragraphs 1 and 2.
2) Unscrew the probe adaptor in a counter clockwise direction,
then remove the adaptor from the chemical lter assembly
as shown in Fig. 13.3.