PREVOST X3-45 Multiplex, Maintenance Manual

Page: 1186 / 1422

Section 22: HEATING AND AIR CONDITIONING
PA1562
44
3. Observe the following factors when
replacing brushes:
a. The face of a new brush is carefully cut
to cause proper seating during the
"wear-in" period.
b. Improper installation can harm both the
brush and the commutator.
c. Replacement brushes should be of the
proper grade.
d. Brush performance will be affected if the
spring and terminal are not properly
placed in the brush tube. The spring
should be free over its entire length and
the terminal should make good contact
with the metal brush tube insert.
9.7.4 Assembly
1. Install washer (3), shaft (5) and rotor
assembly (4) into adapter (7).
2. Install O-ring (2) into housing (1) and
assemble housing to the adapter.
3. Secure housing to adapter using 4
capscrews (6).
9.7.5 Installation
1. Apply gasket cement to the line flanges, put
the two gaskets in place, and connect water
lines to the pump at the flange connections.
Position the pump and motor assembly on
the mounting bracket. Position the
mounting clamps over the motor and
secure with mounting bolts.
2. Connect electrical wiring to the pump motor.
3. Open shutoff valve. Refer to "05 COOLING"
under heading "Draining Cooling System"
for location of valves.
4. Fill the cooling system as previously
instructed in this section under "9.2 Filling
Heating System" , then bleed the system as
previously instructed in this section under
"9.3 Bleeding Heating System" .
9.8 PREHEATING SYSTEM (OPTIONAL)
The preheater is located inside engine
compartment and is accessible through engine
compartment R.H. side door (refer to figure 47).
This Auxiliary Preheating System is used for
preheating and retaining the heat of water-
cooled engines. It can be used before starting
the engine to ease its starting and to provide
immediate inside heat upon operation of the
heating system. It can also be used with engine
running to maintain coolant heat and maintain
the set temperature inside vehicle.
The heater operates independently from the
vehicle engine. It is connected to the cooling
and heating circuits, the fuel system and the
electrical system of the vehicle.
FIGURE 47: LOCATION OF PREHEATER
18607
The pilot lamp turns on when the heater is
switched on. Combustion air flows in to flush out
the combustion chamber and the water
circulation pump is put into operation. The fuel
metering pump conveys fuel in precise doses to
the combustion chamber where fuel and
combustion air form a combustible mixture
which is ignited by the glow plug.
Once the flame sensor has signaled to the
control unit that combustion has taken place
correctly, the glow spark plug and ignition coil
are switched off.
The hot combustion gases are diverted at the
end of the flame pipe, then pass through the
indirect heating surfaces of the heat exchanger
and transmit their heat to the water passing
through the heat exchanger.
The heat is thermostatically controlled and
operates intermittently, i.e. the switched-on
times of the burner vary depending on the heat
requirement. The water temperature depends on
the setting of the built-in water thermostat.