Iveco Daily Euro 4. Manual — part 221
52285
52286
Figure 5
Figure 6
The expansion (block) valve is located between the drier
filter and the evaporator.
Its function is to control and proportion the flow of
refrigerant fluid to get the highest refrigerating capacity out
of the system and to lower the pressure of the refrigerant (at
the filter outlet) to a pre-set value so that the fluid, circulating
in the evaporator, can be drawn up by the compressor in a
completely gaseous form.
The evaporator is a heat exchanger located between the
expansion valve and the compressor.
Its function is to:
- change the state of the refrigerant from a liquid, at the
inlet, to a gas, at the outlet;
- absorb the heat in the cab and thereby produce the
required refrigerating effect.
To be able to perform these functions, an electric fan draws
warm, moist air from the cab and conveys it onto the
evaporator.
Since this air is at a higher temperature than the refrigerant,
it gives some of its heat to the refrigerant and cools down,
while the moisture it contains condenses on the evaporator
fins in the form of droplets.
This produces cold, dehumidified air.
This change takes place with considerable heat absorption.
A special channel collects the condensation formed and
discharges it outside.
The considerable cooling of the radiating pack is due to the
change in state, from liquid to gas, of the refrigerant.
553233
Expansion valve
553231
Evaporator
This valve has two passages for the refrigerating fluid:
- the bottom one enabling the refrigerant to pass (5) from
the drier filter to the evaporator (2). Along this route
there is a spring (4) that, appropriately set, makes it
possible to obtain such a leap in temperature
(overheating) as to make sure that the refrigerant, at the
evaporator inlet, is entirely in its gaseous state. In
addition, there is also a modulating element, in this case
a ball (3) housed in the gauged pipe that controls the
flow rate of refrigerant to the evaporator;
- the top one enabling the refrigerant to pass (1) from the
evaporator to the compressor (6). Along this route
there is a temperature sensor (7) that, depending on the
temperature at the evaporator outlet, makes it possible
to control the flow rate of refrigerant, by means of the
modulating element (3), and control the overheating, by
means of the spring (4).
The drying filter is located between the condenser and the
expansion valve. On the vehicles equipped with the F1C
engine, it is incorporated into the condenser and performs
the following function:
- reserve tank for excess refrigerant fluid during variable filling
phases;
- filtering element for the solid particles generated by
compressor wear;
- eliminating the moisture formed in the system.
52284
Figure 7
553234
Drier filter
The condenser located in vehicles with F1C engine,
has the drier filter incorporated.
NOTE
When the vehicle is stationary or in a traffic jam, the flow of
air needed to transform the refrigerant fluid is produced,
under the control of the three-level pressure switch, by the
fan for cooling the engine coolant.
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CAB AIR-CONDITIONING
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52287
Figure 8
The three-level pressure switch is mounted on the pipe
connecting the drier filter to the expansion valves. It has the task
of operating the electric fan for the condenser and radiator
when the vehicle is stationary or running at low speed, so there
is no air stream caused by the forward motion of the vehicle,
and it is therefore necessary to activate refrigerant condensation
by forced ventilation.
In addition, it has the task of disconnecting the electromagnetic
coupling of the compressor pulley when the pressure of the
fluid (high pressure side), in spite of the action of the condenser
and radiator fan, reaches dangerous limits or when the heating
load conditions are not sufficient to make the refrigerant
evaporate.
It is fitted into the left side rear-view mirror.
The system is equipped with specific devices that, by checking
the pressure and temperature, make it possible to protect the
system from possible trouble and provide optimal operation.
553242
Outside air temperature sensor
CONTROL AND SAFETY DEVICES
Description
553235
Three-level pressure switch
CAB AIR-CONDITIONING
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D
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52289
Figure 9
General
A special casing, configured so as to permit insulation, houses
the radiator-heater, evaporator, fan unit, internal air
(recirculation air) and external air (fresh air) intakes, direction
flaps, ducts and vents for the flow of treated air.
This unit has to control the following parameters and
functions automatically under the control of the control unit:
air temperature at vents, fan speed, air distribution,
recirculation, and compressor activation.
The system needs to make provision for the possibility of
adjusting the following parameters and functions manually:
fan speed on 5 positions, air distributor on 4 positions (5 in
automatic mode), recirculation, and compressor activation.
The manual controls have priority over automatic mode and
are kept in memory until the user deliberately cancels the
command, returning control of the relative function to
automatic mode.
If one of the parameters is changed manually, the others
remain under automatic control.
The air temperature at the vents is always controlled
automatically to produce the temperature shown on the
display in the cab (unless the system is not in operation).
The automatic air-conditioning/heating system is controlled
by an electronic control unit that governs both systems
(air-conditioning and heating) and determines the mixture
and quantity of air to be introduced into the cab to provide
the required conditions.
To obtain the required temperature in the cab, the control
unit also takes into account the data from the sensor that
measures the outside air temperature.
The control unit therefore governs the following functions:
- switching the air-conditioning system on and off;
- using external or recycled air; the hot/cold air mixture;
- the amount of air to introduce into the cab (with the
different fan speeds).
Every time the battery is disconnected, when it is
reconnected the control unit automatically zeroes the
positions.
52290
Figure 10
553248
Electronic control unit
Revi - April 2002
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CAB AIR-CONDITIONING
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AIR-CONDITIONING UNIT (“M. MARELLI” OR “DENSO” TYPE)
Components
Figure 11
1. Strip on A.I. flange
2. Treated air sensor
3. Front door hatch
4. Distribution bushing
5. Recirculation door
6. LH air intake box
7. Cond. drain pipe retaining bracket
8. Mixing actuator
9. Rear box
10. Distribution bushing
11. Complete distribution door
12. Strip
13. Strip
14. Radiating mass
15. Wiring harness
16. Tie rod
17. Distribution lever
18. MAX DEF cam
19. Fan potentiometer
20. Mixing potentiometer
21. Control mounting
22. Knob adapter ring
23. Prism
24. Complete microswitch
25. Control pin
26. Knob
27. Cap spring
28. Cap
29. Condensation drain pipe
30. Strip
31. Condensation drain tub
32. Control unit
33. Condensation drain tub strip
34. Front box
35. Self-tapping insert
36. Mixing/foot door lever
37. Bushing
38. Transmission
39. Vent./demist. door lever
40. Water pipe fixing U-bolt
41. Distribution cam
42. Control mounting bracket
43. Anti-frost sensor
44. Wiring retainer clamp
45. Fan strip
46. Electric fan
47. Connection cover
48. Motor mounting
49. Spacer
50. Connector bracket
51. Electronic control
52. Evaporator
53. Distribution bushing
54. Complete distribution door
55. Evaporator strip
56. Pipe
57. OUT O-ring
58. Expansion valve
59. OUT O-ring
60. Fixing screw
61. IN O-ring
62. IN O-ring
63. Pipe passage strip
64. Pipe strips
65. A.I. actuator
66. A.I. door lever
67. RH air intake box
68. Tie rod
52294
CAB AIR-CONDITIONING
9
D
AILY
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553230
”M. MARELLI” TYPE HEATER/
AIR-CONDITIONER UNIT
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