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Geotechnical Instruments
CODAOM002 Iss.06
3.5 Internal VOC filter
VOCs can affect the reading from the CO sensor. To get over this problem the Diveair analyser has a
filter to remove the VOCs before the gas reaches the CO sensor. The filter is situated within the monitor
and should not normally need replacing between services.
The lifetime of the filter is dependent on the amount of VOCs that it is required to remove. If
contamination of the filter is suspected it can be examined and changed by opening the case. The case
should be opened only in a clean and dry environment. Replacement filters can be obtained from
Geotechnical Instruments.
4
Servicing and Maintenance
It is recommended that instruments are serviced regularly by the manufacturer.
There are no user serviceable components within the analyser apart from those mentioned below.
4.1 Particulate Filter Change
The analyser contains a particulate filter located within the inlet port of the instrument. The filter is
changed as follows:–
1. Remove the sampling tube from the analyser by carefully removing the inlet nozzle.
2. The filter inlet nozzle is removed by using an Allen key (Hex key) to unscrew the inlet nozzle.
When the nozzle is removed, the old filter will be attached to the rear of the nozzle. This filter can
be removed by hand.
3. Carefully locate a new filter onto the rear of the nozzle, ensuring it is firmly located. Carefully
reposition the nozzle, ensuring the sealing O-ring is in place in the nozzle housing and tighten
using the Allen key (Hex key).
4.2 Water/PTFE Filter Change
The Water/PTFE filter consists of a small plastic housing containing a PTFE membrane that has push on
tube fitting at one end and a luer fitting the other.
The analyser should be opened only in a clean and dry environment.
To change the Water/PTFE filter:-
1. Switch the analyser off.
2. Open the analyser. This may require the removal of the security tags (cable ties) before the
analyser can be opened.
3. Carefully twist the leur fitting to undo the connection and release it from the holding clamp.
4. Remove the tube from the other end of the filter.
5. Take the new filter and push the tube onto the hose barb connector on the filter.
6. Put the filter through the clamp and attach and tighten the leur fitting.
7. Close the analyser and replace the security tags.
8. Dispose of the old filter.
4.3 VOC Filter Change
The VOC filter consists of a cartridge that has push on tube fittings at either end.
The analyser should be opened only in a clean and dry environment.
To change the filter:-
1. Switch the analyser off.
2. Open the analyser. This may required the removal of the security tags (cable ties) before the
analyser can be opened.
3. Carefully remove the plastic tube from both ends of the filter tube.
4. Insert the new filter and push the tubes onto the hose barb connectors on the filter.
5. Close the analyser and replace the security tags.
6. Dispose of the old cartridge.
If the contents of the filter escape:
No special disposal procedures required
Wash hands after handling
Consult medical advice if ingested