Generac 86640 - Manual (Page 55)

Section 4.3- COOLING AND VENTILATING AIR
General
Service technicians sho work on the Series NP (recrea­
tional vehicle) and IM (industrial mobile) generators should
be familiar with air flow requirements for these units. Ade­
quate air flow for cooling, ventilation and combustion MUST
be provided or serious problems will result.
Types of Cooling Fans
Engine-generators may be equipped with either (a) a
PUSHER type fan, or (b) a SUCTION type fan. The suction
type fan used on some models is a 'squirrel cage" fan.
Air Flotw- Pusher Fan Units
See Figure 6. A blower fan, attached to the generator
Rotor, draws air into the generator interior to cool generator
internal parts. The heated generator air is expelled through a
blower air outlet duct on the side of the unit. The engine's
"pusher“ type cooling fan draws air around the unit, then
forces the air through the radiator, outward and away from
the unit.
Air Flow- Suction Fan Units
Generator internal parts are cooled in the same manner
as for "pusher" fan units. The suction type engine cooling fan
is a high capacity, squirrel cage type. The fan draws air in and
across the radiator, then directs the air downward and away
from the unit through an air duct. See Figure 7.
Installation Manual
Additional information on cooling and ventilating require­
ments can be found in the "INSTALLATION MANUAL" for
water-cooled RV generators. These manuals can be ordered
from Generac Corporation.
Figure 7. Typical Installation- Unit with Suction Type Fan
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