Low-Buoy; Automatic Tag Unload; Manual Unload; Automatic Mode - PREVOST H3-45 2023 Operator's Manual

inches (100 mm), which may prove useful when
the dock is higher than usual. The front Hi-Buoy
is combined with front kneeling to increase
flexibility of the system.
The full Hi-Buoy system raises the whole coach
about 4 inches (100 mm). It can be used to
enable passengers to get on or off the coach
easily, and to safely travel roads with high
obstacles.
See High Buoy / Low Buoy
and Instruments.
NOTE
The Hi-Buoy system does not operate when the
coach is traveling over 5 mph (8 km/h).
Consequently, the driver cannot inadvertently
operate the Hi-Buoy system at higher speeds.

LOW-BUOY

This system lowers the coach about 4 inches
(100 mm). It enables the coach to drive under
overhead obstacles.
Low- buoy operation is controlled by a rocker
switch on the L.H. dashboard panel. Refer to
High Buoy / Low Buoy
Instruments. A pictogram appears in the Driver
Information Display if the coach speed exceeds
12 mph (20 km/h) when lowered.
CAUTION
Avoid parking too close to the curb or other
obstacles that could damage the coach during
low-buoy operation.
WARNING
Use only below 5 mph (8 km/h).
WARNING
The Low- Buoy cannot be activated when the
coach is traveling over 5 mph (8 km/h).
Consequently, the driver cannot inadvertently
operate the Low-Buoy system at higher speeds.
in Section 4 Controls
in Section 4 Controls and
PA-1652 Operator's Manual H3-45 Coach
NOTE
The Low- Buoy cannot be activated when the
coach is traveling over 5 mph (8 km/h).
Consequently, the driver cannot inadvertently
operate the Low- Buoy system at higher
speeds.

AUTOMATIC TAG UNLOAD

Tag axle unload consists of releasing the air
inside the tag axle suspension air springs, fully
loading the drive axle suspension. Unloading the
tag axle helps cornering at low speed and prevent
the tag axle tires from scrubbing, causing
excessive wear during the rotation process. The
tag axle service brakes do not operate when the
tag axle is unloaded.

MANUAL UNLOAD

The driver can unload the tag axle manually. This
is useful in many situations, such as when the
vehicle is stuck on slippery surface. Unloading
the tag axle transfers extra weight for better
traction to the drive axle wheels.
This self- cancelling mode reverts to Automatic
Mode once the vehicle speed exceeds 20 mph
(32 km/h) for more than 6 seconds.
FIGURE 4: SYSTEM STATUS PICTOGRAM - TAG AXLE
UNLOADED

AUTOMATIC MODE

The tag axle will unload automatically when all
the following conditions are met:
1. The ignition is ON;
2. The steering wheel's rotation exceeds one
turn;
3. The vehicle speed is below 20 mph (32 km/h).
In service, the tag axle will automatically reload if:
1. The vehicle speed exceeds 20 mph (32 km/h)
for more than 6 seconds;
or
Other Features 5-15