PREVOST X3-45 2016, Руководство по обслуживанию, Страница: 402 / 459

Section 22: HEATING AND AIR CONDITIONING
PA1593
4
1. HEATING AND AIR CONDITIONING
The interior of the vehicle is pressurized by its
Heating, Ventilation, Air Conditioning (HVAC)
system. The vehicle is equipped with a Central
HVAC System; air flow and controls divide the
vehicle in two areas: driver’s area and
passengers’ area. The interior of the vehicle
should always be slightly pressurized to prevent
dust and moisture from entering vehicle. Each
section has its own fresh air, returning air and
discharge air ducting. The exhaust is mainly
done through the rear ventilator and through
normal air-tightness losses.
2. AIR CIRCULATION WITH CENTRAL
HVAC SYSTEM
2.1 DRIVER’S AREA
Fresh air is taken from a plenum underneath the
front service compartment and enters the mixing
box through an ON/OFF damper. Return air is
taken through the base of the dashboard panel
utility compartments into the mixing box. Mixed
air goes through cooling and heating coils, fans
and discharge ducts.
Both right and left discharge ducts defrost one
half of the windshield. The driver can also divert
some air flow to the console, from which he can
direct air to his knees and/or upper body with
adjustable HVAC air registers and to his feet
with the appropriate button (see Fig. 1 and
Operator’s manual).
FIGURE 1: DRIVER’S AIR CIRCULATION
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X3-45 coaches are also equipped with a
windshield upper section de-icing system. Also,
one additional air register is located in the
driver’s area but supplied by the passengers’ air
ducting system. It is installed in the stepwell for
step de-icing.
2.2 PASSENGERS’ AREA
Fresh air enters the vehicle on the L.H. side,
through the recirculation damper located inside
the evaporator compartment door (Fig. 2). The
damper can be fully opened for normal operation
or closed for extreme weather or highly polluted
areas (Refer to the Operator's Manual for more
details). The recirculation REC button is located
on the HVAC control unit. Press down the button
to partially close the fresh air damper. Return air
is drawn from inside the vehicle through the
register duct located on L.H. side of vehicle (Fig.
3).
FIGURE 2: PASSENGERS' AREA RECIRCULATION
DAMPER
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A double blower fan unit, which is activated by the
evaporator motor, draws mixed air through an air
filter, cooling and heating coils, then forces this air
in the ventilation ducts along the walls, and finally
exhausts it just below side windows.
X3-45 coaches are also equipped with an
overhead compartment ventilation system, a
three-position rocker switch (0FF - 1
st
speed
- 2
nd
speed) located on R.H. dashboard panel
controls the speed of both fans. Return air is
drawn just below the middle side windows
through an air filter into the overhead
compartment fan; discharge air is fed to the
rotating registers through the ventilation duct (Fig.
4).