September
2017
Sentinel V SC and RT Operation Manual
Page 124
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Replacing the O-Ring
TRDI strongly recommends replacing the O-ring whenever the Sentinel V ADCP is opened. Inspecting
and replacing the O-ring should be done before sealing the ADCP.
There is no need to disconnect the end-cap cables or lanyard to replace the O-ring. The O-ring
is large enough to stretch over the end-cap.
The O-ring sits in a dove-tail groove. This makes it less likely to fall out when the system is
opened. Use the O-ring tool to pry it out of the groove.
Never use metal tools as this may
damage the O-ring groove or the housing flange.
The O-ring is size 2-163 for both transducer and end-cap side of the housing.
To replace the O-ring:
1. Remove the end-cap or transducer head (see
Disassembly and Assembly Procedures
).
2. Insert the O-Ring tool tip on the inside edge of the groove and gently slide it around
the groove perimeter to lift the O-Ring.
Figure 62.
Using the O-Ring Removal Tool
3. Inspect the O-ring. When viewed with an unaided eye, the O-ring must be free of cuts, indenta-
tions, abrasions, foreign matter and flow marks. The O-ring must be smooth and uniform in ap-
pearance. Defects must be less than 0.1 mm (0.004 in.).
If the O-ring appears compressed from prior use, replace it. Weak or damaged O-rings will
cause the Sentinel V ADCP to flood.
4. Clean and inspect the O-ring groove and the plastic housing flange. Also check the mating surface
on the transducer and end-cap. Be sure they are free of foreign matter, scratches, indentations,
and pitting.
Check the O-ring groove thoroughly. Any foreign matter in the O-ring groove will cause the
Sentinel V ADCP to flood.
