PREVOST X3-45 COMMUTER User Manual

SECTION 22: HEATING AND AIR CONDITIONING
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DOB 1300-1556 | X3-45 Commuter PA-1648 Maintenance Manual First release Oct 2020
6.3 HVAC SYSTEM OPERATION
To operate the HVAC system when the vehicle
is stationary, engine should run at fast idle.
During operation of the HVAC system, windows
should be kept closed and door not left open
longer than necessary. In order to prevent
battery discharge, the HVAC system will not
operate if the battery voltage drops below 24
volts.
The vehicle is divided into two areas:
• Driver’s area (driver’s HVAC unit).
• Passengers’ area (passengers’ HVAC
unit).
The A/C compressor starts automatically when
the two following conditions are satisfied:
1. The outside temperature is above 32°F
(0°C).
2. The passengers’ area temperature is
within 7° (4°C) of the set point or higher.
(if set point is 68°F for example, return
air temperature must be above 61°F, at
this moment, enough heat is available
from the engine to warm up the area
while the air conditioning will remove
moisture in air and prevent fogging up of
the windows).
NOTE
Upon starting if the outside temperature is
above 32°F (0°C) and then drops below 32°F
(0°C), the compressor will keep running up to
a temperature of 15°F (-
9°C) to prevent
fogging up of the windows.
NOTE
To perform a test of the driver's section
windshield defroster, it is possible to run the
system without running the engine.
6.4 HVAC CONTROL UNIT
The vehicle is divided into two areas:
1 - Driver’s area (driver’s HVAC unit)
2 - Passengers’ area (passengers’ HVAC unit)
Fresh air is fed in each area and has a separate
return air and discharge air duct.
Both driver and passengers HVAC units turn on
automatically at starting of the engine but the
driver can turn both off if desired and can then
turn them back on using the ON/OFF button on
the HVAC control unit.
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The HVAC control unit is used to control
heating, ventilation, air conditioning and
defroster in the driver’s area only. The
passengers’ area HVAC unit (passengers’ unit)
temperature and fan speed is fully automatic. It
has a preset temperature of 68°F (20°C). The
temperature and fan speed cannot be changed
by the driver.
NOTE
It is recommended to run engine at fast idle to
operate the air conditioning system when the
vehicle is stationary.
This will improve A/C compressor performance
and provide adequate electrical power to the
multiple A/C system fans.
When the system is running, keep roof
ventilation hatch and door closed to prevent
cooling loss.
To prevent battery run-down, the central HVAC
unit will not operate if the battery voltage drops
below 24 volts.
When the HVAC system is in operation, park at
least 4 feet from other vehicles or buildings to
allow sufficient air flow through the condenser
coil.
The HVAC control unit performs a self-test every
time it is turned on. Codes are shown on
displays or flashed on control buttons.
The A/C compressor starts automatically when
the two following conditions are satisfied:
1. The outside temperature is above 32°F
(0°C).
2. The passengers’ area temperature is
within 7° of the set point or higher (set
point is 68°F, so return air temperature
must be above 61°F, at this moment,
enough heat is available from the engine
to warm up the area while the air

PREVOST X3-45 COMMUTER Specifications

General

Engine	Volvo D13
Transmission	Allison B500
Fuel Type	Diesel
Length	45 ft (13.7 m)
Width	102 in (2.6 m)
Horsepower	500 hp
GVWR	54, 000 lbs
Height	141 in