Campbell Scientific AP200 CO2/H2O Atmospheric Profile System - Manual (Page 59)

AP200 CO
2
/H
2
O Atmospheric Profile System
Some common causes of leaks include:
• Forgetting to tighten a fitting during the installation. It is good
practice to check all of the tube connections before turning the system
on. If a fitting can be loosened with fingers, it is not properly
tightened.
• Dirt or debris in the tube fitting. Use care when connecting or
disconnecting tubes, and install caps and plugs on tubes and fittings
when they are not in use.
• Excessive bending. Be careful to observe the minimum bend radius
and avoid bending the tube near the end at the connections.
7.2 Enclosure Desiccant
Check the humidity indicator card in the mesh pocket in the AP200 system
enclosure door. The humidity indicator card has three colored circles that
indicate the percentage of humidity. Desiccant packets inside the enclosure
should be replaced with fresh packets when the upper dot on the indicator
begins to turn pink. The indicator card does not need to be replaced unless the
colored circles overrun.
Campbell Scientific strongly suggests replacing desiccant
instead of reactivating old desiccant. Improper reactivation
can cause the desiccant packets to explode. If the user is
determined to reactivate old desiccant packets, follow the
procedure provided in the ENC16/18 User Manual.
The replacement desiccant pack is the 4905 Single 4-Unit Silica Desiccant
Bag. (The 4905 can be purchased in quantities of 20 as pn 6714.) The
replacement humidity indicator card is pn 28878.
If the desiccant packs are being replaced very frequently, make sure the
feedthrough cap is properly installed (see Section 5.3.3, Power, and FIGURE
5-19). In very humid conditions, it may be helpful to seal the cable feedthrough
with plumber’s putty.
7.3 Intake Filters
The sample flow will decrease over time as particulates clog the intake filters.
Eventually, the flow will be reduced to the extent that it will degrade the
equilibration time after an intake is selected. As a general guideline, the filters
should be replaced when the flow decreases by 25%. The filters will normally
last a few months, but will require more frequent changes in conditions with
high particulate matter in the air.
To change the intake filter, first turn the pump off to avoid pulling dirty air into
the system.
Open the cover of the intake assembly as shown in FIGURE 5-14. The rain
diverter, intake assembly with filter, and intake tubing are shown in FIGURE
5-15.
Press the rain diverter upwards and out of the bracket as shown in FIGURE
7-1.
CAUTION
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