SYS11000OM Rev G
[UF 350-HD, Generic Template]
FLIR Systems Polytech AB
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1.2.4
Desiccant checks and maintenance
The TCU is equipped with two Desiccator Breathers to control the internal environment
and to maintain the components in good condition. The desiccators should be checked
before each mission as a part of the pre-flight check.
NOTE:
If the TCU recently has been operated in a high humidity environment, the desiccants may require
up to 4 hours for stabilizing and giving a correct humidity reading.
The TCU also has a built in Desiccator Indicator providing a visual indication of the
moisture content. A blue reading is an indication that the internal atmosphere is dry, while
a pink reading indicates that high levels of moisture are present.
A partial blue and pink reading is an indication that a moderate level of moisture is
present, which is considered normal and acceptable.
If just the two Desiccator Breathers (not the Indicator) are indicating that moisture is
present, then just the Breathers needs to be dried using FLIR Systems Polytech AB
GEN00035 Desiccator Dryer Kit or P990024 Refill Kit for Breathers, or replaced with new
P990002 Desiccant Breather(s).
If the Desiccator Indicator indicates moisture (>40%), the drying procedure (purging)
needs to be performed. (See § 1.2.5 and 1.8.8)
After purging, all three (3) desiccators should be replaced or dried using the GEN00035
Desiccator Dryer Kit / P990024 Refill Kit for Breathers.
Desiccator Indicator
(1 ea)
P/N: P990001
Indicates pink if moisture level is >40%
Desiccator Breathers
(2 ea)
P/N: P990002
Indicates pink at two moisture levels; 15% and 30%
(Refill Kit P/N: P990024)
