NorthStar 491 Install Manual page 13

Cleaning a
transducer
491 INSTALLATION MANUAL Revision A
Paint exposed housing
and bore up 30mm (1-1/4")
detail
including exposed end, paddle wheel cavity and paddle wheel
Anti-fouling paint (B744V shown)
FIGURE 4: Anti-fouling paint areas (for Airmar B744V)
CAUTION!
To clean the transducer of heavy debris or foul sea growth, use a stiff
brush or putty knife, but don't scratch the surfaces. Check the transducer
every few weeks, maximum.
Use sanding sparingly, as repeated sanding may affect the transducer's
performance at high speeds. For lighter cleaning, the surface may be
wet-sanded with #220 or finer wet/dry sandpaper.
SECTION TWO — Installing the transducer
housing
paddle wheel
Paint outside wall below the lower O-ring
Use special transducer paint. Other paints may
contain copper, which is conductive and can burn
out the transducer within minutes!
insert
lower
O-ring
PAGE 9