Air Circulation; Auxiliary Unit; System Operation; Driver's Unit - PREVOST H3-41 Maintenance Manual

SECTION 22: HEATING AND AIR CONDITIONING
FIGURE 86: CONDENSER CONFIGURATION X3-45 VIP
7.3

AIR CIRCULATION

Fresh air is taken from behind the R.H. side
headlights assembly (H3 series) or from a
plenum underneath
compartment (X3 Series) and enters the mixing
box through a damper. Return air is taken
through the right console 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
his air flow to the dashboard, from which he can
direct vent to his upper body with adjustable
HVAC register and to his feet with the
appropriate button (see
Owner's manual).
FIGURE 87: DRIVER'S UNIT AIR CIRCULATION
70 PA1621 Maintenance Manual All Series | Revised February 2019
the front service
FIGURE 87 and
7.3.1

Auxiliary Unit

H3 VIP vehicles equipped with the small HVAC
system are equipped with an auxiliary system
that provides five additional registers. Three are
located behind the driver's seat and the other
two are located near the entrance door, at
bottom of first lateral window. The auxiliary unit
comes with cooling and heating coils, fan and
discharge ducts.
7.4

SYSTEM OPERATION

7.4.1

Driver's Unit

The small HVAC system driver's unit is similar to
the central HVAC system driver's unit, except
that the circulating pump is located on the ceiling
of the spare wheel compartment (Figure 9).
On H3 VIP series vehicles, an auxiliary unit is
added in series on the return line of the small
system, it increases the whole system heating
capacity and gives the driver more options.
The temperature control in the driver's area is
provided directly by the HVAC control unit
mounted on the dashboard R.H. side.
NOTE
X3 Series - The driver's area air temperature
sensor is located behind the grill of the R.H.
side console.
NOTE
X3 Series - The outside air temperature sensor
is located near the RH headlight.
7.4.2

Auxiliary Unit - H3 Vip Vehicles Only

The temperature control is provided by the small
system HVAC control unit. The R.H. portion of
the HVAC control unit enables to actuate the
auxiliary unit and to regulate the fan speed.
FIGURE 88: CONTROL UNIT - SMALL HVAC SYST.
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