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© 2017 Nortek AS
7.3
Cable Care
Do not pull on the cable to disconnect connectors.
Avoid sharp bends at cable entry to connector.
Ensure that the cable is fixed to the mounting fixture to avoid mechanical stress to the
connection.
Elastomers can be seriously degraded if exposed to direct sunlight or high ozone levels for
extended periods.
7.4
O-ring Care
Watertight sealing of the instrument housing is provided by double O-rings on the head. The outer O-
ring forms the primary seal and the inner forms a secondary (or backup) seal. If the integrity of the O-
rings are degraded the instrument should not be re-deployed. In this case, please contact Nortek.
O-rings are the critical component that keeps water out of the housing and thus the instrument dry
and functioning. Make a routine of inspection, maintenance and replacement of exposed O-rings.
Properly greased O-rings will help maintain sealing integrity and minimize O-ring degradation. Use
enough grease to lubricate the O-ring thoroughly, but not so much that it will attract additional
debris.
Check the O-rings and the O-ring grooves for grit, hair, lint, sand, or anything that could potentially
breach the O-ring seal.
Clean the groove with a lint free swab or the folded edge of a paper towel.
After frequent missions or if O-rings or groves appear dirty, remove O-rings and clean the groves.
To remove O-rings, use finger pressure or the rounded edge of a plastic card to lift the O-ring out of
the grove. Caution! Never use a metal object to remove an O-ring. It may cause damage to the O-
ring or the sealing surface.
To check O-rings for damage, place the O-ring between the middle and index finger and thumb.
Then pull the O-ring through your fingers, feeling for any debris or wear.
If O-rings are dirty, it is best to replace them. Washing dirty O-rings with soap and water is not
recommended. Soap breaks down the lubricants and will compromise the integrity of the seal.
7.5
Securing Screws
When installing end caps and sensor heads, care should be taken when tightening the screws.
Use the cross tightening sequence. Tightening one screw fully before continuing on to the next
may cause improper O-ring seating and very high mechanical stress concentrated around the
screw hole. This may cause leaks and/or damage to the head or the end cap.
After tightening the screws so that the spring washers are flat, turn each screw a quarter of a turn.
At this point, the O-ring is fully compressed and the instrument is sealed.
Over-torqueing has no positive effect and may damage the threads and/or area around the screw
holes on the head and end cap. Keep in mind that ocean pressure holds the end cap tightly, all the
screws have to do is to secure the end cap from falling out when the system is above water.
7.6
Replacing Desiccant Bag
Humid air can condense enough water to damage the electrical circuitry. At least once a year,
replace the desiccant located in the pressure case. Follow the procedure under Opening the Housing
for the details on opening the housing.
