Section 22: HEATING AND AIR CONDITIONING
PA1562
37
9. HEATING SYSTEM
The schematic of figure 36 shows the central
heating system with its components.
In addition to the normal heating provided by the
engine, a preheating system (104,000 Btu/hr)
(optional) may have been installed in the
vehicle.
9.1 DRAINING HEATING SYSTEM
To drain the entire system, refer to Section 05,
“Cooling”. If only the driver’s or main heater core
must be drained, refer to the following
instructions.
9.1.1 Draining Driver’s Heater Core
1. Stop engine and allow engine coolant to
cool.
2. Locate the normally open water pneumatic
valve on the ceiling of the spare wheel
compartment (Fig. 37), move the pilot-
solenoid valve red tab to close the valve.
WARNING
Before proceeding with the following steps,
check that coolant has cooled down.
3. Loosen hose clamp, install an appropriate
container to recover coolant, and
disconnect silicone hose from water
solenoid valve.
4. From inside of vehicle, remove the two
finishing panels in front of unit. Remove the
three screws fixing the unit front panel.
Open the manual vent located inside the
HVAC unit, on the driver’s side (Fig. 38) to
ensure an efficient draining.
FIGURE 37: CEILING OF THE SPARE WHEEL
COMPARTMENT
22324
FIGURE 38: DRIVER’S HVAC UNIT 22328
9.1.2 Draining Main Heater Core
1. Stop engine and allow engine coolant to
cool.
2. Close both heater line shutoff valves.
On X3 Coaches, the valves are located in 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
(Fig. 39).
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