Onan DYG Series Operator's Manual And Parts Catalog page 13

EXHAUST SYSTEM
Exhaust fumes are noxious. Inhalation can cause death.
Carbon monoxide (CO) is an odorless, colorless gas formed by incomplete combustion of
hydrocarbon fuels. Design and installation of an exhaust system is important for two reasons: one is
fume evacuation; the other reason is the high temperatures the materials must withstand. The gauge or
size of materials used is determined by the maximum allowable back pressure, and length of the
exhaust system. In cases where an engine is exhausted through, the roof of a building, it may be'
necessary to use an exhaust booster fan to aid fume evacuation, and keep back pressure within
specified limits. The pipe attached to the exhaust manifold should be flexible enough to compensate
for thermal expansion, contraction. It should also be able to absorb vibrations. This is extremely
important on turbo-charged units where a rigid piece of exhaust pipe could impart enough stress and
weight to severely damage both turbo-charger and housing.
Where pipe is joined, make sure the joint welds are leak-free. Exhaust ducting which is run along a
combustible wall should be far enough from the wall to prevent heat or fire damage. Where pipe is run
through a wall, a thimble should be installed which will adjust forthermal movement and also prevent
exhaust heat from damaging the wall. Sharp bends should be avoided, but where this is not possible, a
condensation trap should be installed. Drain this trap frequently. Do not terminate an exhaust pipe in
the vicinity of ventilating air inlet duct or venturi, otherwise exhaust gases will be pulled back into the
building.
E X H A U S T FUMES
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