Cooling And Ventilating Air - Generac Power Systems quietpact 85d Owner's Manual

Installation
2.3 COOLING AND VENTILATING
AIR
It is absolutely essential that an adequate flow of air for cooling,
ventilation, and engine combustion be supplied to the generator
set. Without sufficient airflow, the engine/generator quickly over-
heats. Such overheating can cause serious operating difficulties
and also may cause fire and personal injury. The installer must
make sure that sufficient air is available to the generator for cool-
ing, ventilating, and combustion. The installer also must provide
a path for exhausting the cooling air to the exterior of a compart-
ment, if so equipped.

NEVER use discharged cooling air for heating
or permit such air to enter the vehicle interior.
This air contains deadly carbon monoxide gas
and other poisonous, flammable, or explosive
gases.
2.3.1 GENERATOR AIRFLOW
This unit uses an impellar fan located on the alternator drive pulley
to cool the alternator's internal components. Air is drawn through
the alternator and expelled radially behind the drive pulley. An
engine-driven centrifugal blower draws in cooling air through air
inlet openings, moves that air around the engine/generator and
across the radiator, then discharges that air out the bottom (see
Figure 2.7).
Figure 2.7 – Airflow Through Engine/Generator
26
2.3.2 COOLING AIR INLET OPENINGS
The minimum size of the air inlet opening, whether the generator
is housed in a conventional compartment or not, is at least 150
square inches (975 cm 2 ) (see Figure 2.8). This rule applies
whether inlet air is brought in through an opening in the compart-
ment door, an opening in the vehicle skirt, through duct work, or
by any other means.
Screening, louvers, or expanded metal that cover air openings
restrict airflow. Compensate for this by making the actual air
opening proportionately larger. See the "Compensating for
Restrictions" section.
Figure 2.8 – Air Inlet in Compartment Door
When the unit is installed on a suspended mounting system, one
of several different methods of supplying airflow may be used as
follows:
• Provide a door in the vehicle skirt having an air inlet opening
(Figure 2.9).
Figure 2.9 – Suspended Mount: Inlet Door
• Use duct work (Figure 2.10). The installer must be sure air is
available to the sides of the generator for proper air intake.
• Provide an opening in the vehicle skirt and space around the
generator for cooling airflow (Figure 2.11). Recommended
clearance around all sides of the generator is at least two
inches (50 mm).
NOTE: