.
Typical Installations
All
water injected exhaust systems must be designed
so
that
the
discharge water
will
not
flow
back
into
the
engine. There are several methods that can be used
to
keep water out of the engine.
All
are based on
injecting the water at
a point
a
few inches approx-
imately
4
inches
(102
rnm)
below the exhaust mani-
fold outlet and installing a sharp drop
in
the exhaust
line that water cannot normally flow over. These
methods are divided into two general categories:
above water line and below water line installation.
Above
WaterLine: The exhaust manifold must be one
foot
or more above the load water line and the water
must be injected near the exhaust manifold. The
exhaust pipe is pitched downward
1/2
inch per foot
(13
mm
per
305
mm)
to
allow draining in the line
'
whether the genertor set is running
or
stopped.
Below Wafer Line: An Onan Aqualift muffler may be
used for below the water line installations if the lift
height is no greater than four feet
(1220 mm).
A
siphon break is required when the water injection
elbow is below the water line (seeFigure5)
to prevent
water from being siphoned into theexhaust manifold.
The siphon break will be mounted at least
12
inches
(305
mm) above
the
load water line.
If the
lift
height is greaterthan four feet
(1220
mm), a
riser exhaust system will be used. The exhaust
system
will
run
in
a
loop above the water line to a
point
12
to
18
inches
(305
to 457 mm) above the boat
load water line. A water jacket encloses the loop and
the water
is
injected on the outlet side at a point four
inches
(102
mm)
above the bottom of the loop.
A
condensation
trap
is
usually
installed
atthe
bottom
of
the dry exhaust line seciton. Drain the trap at regular
intervals
to
remove condensation.
Generally, exhaust systems
should
be
as
short as
possible with a minimum number
of
bends. The
radius of any bend in the exhaust pipe should be at
least
5
times the diameter
of
the pipe. The
dry
sections of exhaust line should be either insulated or
water jacketed.
Be sure the slotted opening in
fbe
EEEEl
vacuum reiief valve is open to atmos-
pheric pressure. The siphon break wiii not function if
the relief valve slot
is
closed in any way.
11
Ik
HANGERSTRAPS
VACUUM
RELIEF
RUBBER
HOSE
ATER
OUTLET
HAUST
WATER
ECTION
ELBOW
EXHAUST
OUTLET
FIGURE 5.
SIPHON
BREAK
EXHAUST
GAS
1s
DEADLY!
Exhaust gases contain carbon monoxide, a poisonous gas that might cause
unconsciousness and death.
it
is an odorless and coiorless gas formed during
combustion
of
hydrocarbon fuels. Symptoms
of
carbon monoxide poisoning
are:
Dizziness Vomiting
Headache
Weakness and Sleepiness
Muscular Twitching
'
Throbbing in Temples
if you experience any
of
these symptoms, get out into fresh air immediafeiy,
shut down the unit and do not use unfll
if
has been lnspected.
The best protection against carbon monoxide inhaiafion is proper installation
and regular, frequent inspections of the complete exhaust system. lfyou notice
a change in the sound or appearance
of
exhaust sysfem, shut
the
unlf down
immedlafeiy and have
It
inspected and repaired at once by a competent
mechanic.
15
Redistribution or publication of this document,
by any means, is strictly prohibited.
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