SECTION 22: HEATING AND AIR CONDITIONING
44
DOB 2490-2789 | X3-45 Commuter PA1605 Maintenance Manual (Final Version – Rev.2 April 2016)
Draining Main Heater Core
1. Stop engine and allow engine coolant to
cool.
2. Close both heater line shutoff valves.
The valves are located in the engine
compartment. One is on the L.H. side of
compartment in front of the radiator and the other
valve is located under the radiator fan gearbox
(Figure 52).
FIGURE 52: HEATER LINE SHUT-OFF VALVES
FIGURE 53: EVAPORATOR COMPARTMENT
3. The main heater core drain cock is located
in the evaporator compartment. To access
the valve on X3-45 coaches, open baggage
compartment door located in front of the
evaporator compartment (L.H. side). Open
access panel by turning the three screws of
panel ¼ of a turn.
WARNING
Before proceeding with the following steps,
check that coolant has cooled down.
4. Open drain cock in bottom of heater core,
you can unfasten a hose connection on top
of heater core (Figure 53) in order to allow
air to enter while draining.
8.2 FILLING
HEATING
SYSTEM
1. Ensure that the drain hose is reconnected
and the manual vent and drain cock are
closed.
2. Open the surge tank filler cap and slowly fill
the system to level of filler neck.
3. After initial filling, the water shut-off valves
should be open and the water circulating
pump should be energized to assist in
circulating coolant through the heating
system. To perform this operation, start the
engine, switch on the HVAC control unit,
both driver and passengers’ sections, and
set temperature to the maximum position in
order to request the heating mode in each
of these sections.
4. When coolant level drops below the surge
tank filler neck, slowly fill the system to level
of filler neck.
5. Once the level has been stabilized, replace
cap.
8.3 BLEEDING
HEATING
SYSTEM
Whenever the heating system has been drained
and refilled, or the system has run low on
coolant and coolant has been added, it is
necessary to bleed air from heating system.
Locate the manual vent illustrated in Figure 49 ,
and open momentarily until no air escapes from
the line.
8.4 SOLDERING
Before soldering any part of the system, make
sure the area is well ventilated. Use (stay clean)
flux sparingly and apply solder (95-5 round wire
1/8 inch). After completing repairs, test for leaks.
