Westerbeke 9.0 BCG Technical Manual page 23

when used, must have its vent hose or tube routed so as to be above the water line and to remain empty of
water when the engine is shut down to allow air to enter through this vent and prevent siphoning. The
generator exhaust system must
not
be combined with other exhaust systems. The generator should have
it's own system
Exhaust Back-Pressure
The exhaust discharge hose must be of adequate size and
minimal run to prevent excessive exhaust back-pressure.
Exhaust back-pressure should be checked before a gener-
ator is put into service. (Refer to the illustration.) Excessive
back-pressure will affect the engine's performance and the
generator's power output.
To measure the engine's back-pressure, either a mercury
manometer, a water column, or another pressure measuring
gauge has to be used. If the generator set does not have a
tapped hole in its exhaust elbow, one must be drilled and
tapped for a 1/8 inch NPT fitting.
Measure the engine's back-pressure at the exhaust elbow
while the generator is under a full load. Back pressure, as
measured by a gauge instrument, should not exceed the
following specifications:
2 inches of mercury
27 inches of water in a water column
15.6 ounces PSI
1.0 PSI
\
Exhaust
Elbow
Exhaust
Excessive back-pressure can be caused by a small diameter exhaust hose, a small muffler, sharp bends in
the exhaust hose, fittings, water pockets, and a high volume of water in the exhaust system due to the length
of the exhaust discharge hose. The use of elbows and fittings in the exhaust discharge hose's routing should
be limited since these will create flow restrictions and contribute to exhaust back-pressure. The generator's
exhaust system tmJ$. be separate from any other engine's exhaust system. Dry portions of the exhaust
system between the engine's exhaust manifold and the water injected exhaust elbow must be insulated to
hold in the heat. Dry stack type
exhaust systems must be attached
to the generator engine's exhaust
manifold by means of a flexible con-
nector pipe. This system must be
properly supported and insulated
to prevent water entry into the
engine's cylinders. Provisions
must be made for the discharge of
the engine's cooling sea water.
17
"'LAPPE"
COVE.-
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I
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DRY STACK EXHAUST
Westerbeke Generators