SECTION 22: HEATING AND AIR CONDITIONING
8
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016)
2. AIR CIRCULATION
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 Figure 5 and
Operator’s manual).
FIGURE 5: DRIVER’S AIR CIRCULATION
22307
2.2 PASSENGERS’
AREA
Fresh air enters the vehicle on the L.H. side,
through the recirculation damper located inside
the evaporator compartment door (Figure 6). 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
(Figure 1).
FIGURE 6: PASSENGERS' AREA FRESH AIR DAMPER
22302
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 (FIGURE 4) along the
walls, and finally exhausts it just below side
windows.
X3-45 Commuter coaches are also equipped with
parcel rack A/C system An ON-OFF rocker switch
located on R.H. dashboard panel allows
activation of both fans. Return air is drawn just
below the middle side windows through an air
filter into the parcel rack A/C system fan.
Discharge air is fed to the rotating registers
through the ventilation duct (Figure 7).
The parcel rack air registers are used to control
air flow for the passenger seats. Direct air flow
by pointing or rotating the register. Open or
close the register to adjust the air flow.
FIGURE 7: PASSENGERS’ PARCEL RACK VENTILATION
SYSTEM
22211
