September
2017
Sentinel V SC and RT Operation Manual
Page 106
EAR-Controlled Technology Subject to Restrictions Contained on the Cover Page.
Replacing the Transducer Head Assembly
To replace the transducer head assembly:
1. Stand the Sentinel V ADCP on its end-cap on a soft pad.
2. Inspect, clean and lubricate the O-ring on the housing (see
). Ensure that the
O-ring is firmly pressed into the groove.
TRDI recommends using a new transducer head O-ring whenever the ADCP is opened.
3. Replace the desiccant (see
). Ensure that the desiccant will not press on
the electronics.
4. Reconnect the internal I/O connector.
5. Gently lower the transducer head/electronics assembly into the housing, aligning the mating
holes and the alignment mark embossed on the transducer with the alignment mark embossed on
the housing. When mating the housing with the transducer head flange try to apply equal pressure
to all parts of the O-ring. Make sure the face O-ring remains in the retaining groove.
Check that no wires or any other object is pinched between the transducer head and the
housing. If the O-ring is not in the groove or if a wire or other object is pinched, the Sentinel V
ADCP will flood.
6. Examine the transducer head assembly bolts and washers for corrosion; replace if necessary.
7. Check the housing captive nuts are not stripped or worn. Replace as necessary (see
). Captive nuts snap into place with the small bump facing the housing.
8. Tighten all four sets of hardware until “finger tight.”
9. Tighten the bolts in small increments in a “cross” pattern until the split washer begins to flatten
out and then use a torque wrench to tighten the bolts to the recommended torque value of 1.7 Nm
(15 Pound-Force Inch).
Apply equal pressure to the O-ring as the bolts are tightened. If one bolt is tightened more
than the others, the O-ring can become pinched or torn. A damaged O-ring will cause the
system to flood.
Do not over tighten the bolts that hold the transducer, housing and end cap together. If the
bolts are over-tightened, the housing bolts or captive nut threads can strip, crack, or break
causing the system to flood. On the other hand, leaving the bolts too loose can cause the
system to flood.
If a torque wrench is not available, tighten the bolt until the split washers are flat, and then
turn the bolt ¼ turn more.
