Get Air Conditioning -> Checking the Efficiency of the Air Conditioning System Guide for Citroen C3 SUV First Generation (2002-2009)

CHECKING THE EFFICIENCY OF THE AIR CONDITIONING SYSTEM

CHECKING TEMPERATURES

TOOLS

Checks.

Two thermometers

If all these conditions are met, take the following action :

- Start the engine, with the air conditioning off, and wait for the cooling

fan first speed to cut in.

Preliminary conditions.

- Operate the air conditioning and set the engine speed to 2500 rpm.

Position of the air conditioning controls :

- Maximum cold air.

- Air blower in maximum position.

- Air distributor in "ventilation" position, with the dashboard vents open.

- Air intake flap in "exterior air" position.

NOTE : If the ambient temperature reaches 40°C, the engine speed

will return to 2000 rpm in order to prevent the compressor from being

cut off by the High Pressure safety device (Pressostat).

After the air conditioning has been on for three minutes, measure :

- the ambient temperature in the workshop,

- the temperature of the air coming from the central vents.

Conditions and vehicle equipment.

- Boot closed.

- Doors and windows shut.

Compare the two values using the table on the following page.

- Ensure the vehicle is in a sheltered area (away from wind, sun, etc.).

220

CHECKING THE EFFICIENCY OF THE AIR CONDITIONING SYSTEM

CHECKING TEMPERATURES (continued)

Vehicle using R134.a fluid (Compressor with variable capacity)

40

35

30

25

20

15

Ambient temperature in °C

Vehicle

Engine types

Air temperature

from the central vents

in °C

15 ± 2

C3

All types

18.5 ± 2

10 ± 2

12.5 ± 2

8.5 ± 2

6.5 ± 2

221

CHECKING THE EFFICIENCY OF THE AIR CONDITIONING SYSTEM

CHECKING PRESSURES

TOOLS - 1 Charging station.

CHECK

- 2 Thermometers.

- The temperature of the air coming from the central vents (see table).

- The High Pressure.

- The Low Pressure.

Once the preliminary conditions, vehicle equipment and checks have

been fulfilled (see table) : After the air conditioning has been on for three

minutes, record the following parameters :

Compare the values recorded with the table below, or the graphs.

Vehicle using R134.a fluid (Compressor with variable capacity)

Ambient temperature in °C

Vehicle

40

35

30

25

20

15

Engine types

All types

High pressure (Bars)

Low pressure (Bars)

14.5 ± 2

17.6 ± 2

20 ± 2

21.4 ± 2

2.8 ± 0.2

23.6 ± 2

3 ± .02

25.2 ± 2

3.5 ± .02

C3

2.4 ± 0.2

2.5 ± 0.2

Note : For vehicles with RFTA (1), disconnect the connector of the air inlet motor, ensuring that it is in the outside air position.

Reminder: The above results are expressed in absolute bars. If using equipment for measuring relative pressure

(e.g. manifold), the value can be increased in order to bring it up to absolute bars.

(1) RFTA = Fully automatic air conditioning.

222

CHECKING THE EFFICIENCY OF THE AIR CONDITIONING SYSTEM

CHECKING PRESSURES (continued)

Low pressure

too low

Low pressure

too high

Low pressure

normal

High pressure

too low

- Insufficient fluid charge.

- Constriction of the HP system.

- Dirty pressure control valve.

- Cooling fan speed unsuitable.

- Faulty compressor.

- Faulty pressure control valve.

- Faulty compressor.

High pressure

normal

- Faulty compressor.

- Dirty evaporator.

- Circuit normal.

- Cooling fan speed unsuitable.

- Faulty pressure control valve.

- System blocked.

- Water in the system.

- Presence of solid matter in the

system.

- Dirty condenser.

- Excessive fluid charge.

- Dirty condenser.

- Faulty pressure control valve.

- Cooling fan speed unsuitable.

High pressure

too high

Checking the pressure at temperatures between 15°C and 35°C for information only.

In general, the pressure should be approximately:

- For R134.a fluid, less than 2 Bars (Low pressure), and between 13 and 24 Bars (High pressure).

223

AIR CONDITIONING SYSTEM R 134.a

(1) Low pressure valve.

(2) High pressure valve.

(3) Filter.

(4) Pressostat

Tightening torque m.daN

(a)

(b)

(c)

(d)

(e)

(f)

: 0.6.

C5HP17SP

224

AIR CONDITIONING SYSTEM R 134.a

Testing procedure

Conditions inside the vehicle

Positions of the air conditioning controls :

Maximum cold.

Switch on the air conditioning and adjust the engine speed to 2500 rpm.

In an ambient temperature of 40°C, the engine speed will be brought

down to 2000 rpm, in order for the pressure safety threshold to cut off

the compressor.

Maximum blower power.

Air distribution on «ventilation» with the air vents open.

Position the air inlet flap to outside air.

For further temperatures/pressures: see Tables on pages 224 and 225,

WARNING: For RFTA (1), disconnect the air inlet motor connector, first and Graph on page 229.

ensuring that it is in the outside air position.

(1) RFTA = Fully automatic air conditioning.

After 3 minutes of operation, note down the following 3 parameters:

- The temperature of the blown air coming out of the 2 central air vents

(take the average).

Test procedure.

When all these conditions are met, proceed in the following order:

- The high pressure, via the intermediary of the clickfit union (at the pres-

Measure the temperature in the workshop approx. one metre in front of sure reducer inlet).

the vehicle’s air inlet grille.

- The low pressure, via the intermediary of the clickfit union (at the pres-

Start the engine (without the air conditioning, or the blower, operating) sure reducer outlet).

and wait for the cooling fan slow speed to trigger (should the engine tem- NOTE: The low and high pressures are absolute pressures.

perature not rise sufficiently, it is permissable to increase the engine When measuring the blown air temperatures, avoid any contact between

speed to 2000 rpm).

the thermocouple and the air vents.

Once it is sufficiently hot in the engine compartment, return the engine to

idle and commence the test.

At the conclusion of the test involving vehicles with «RFTA», do not

forget to reconnect the air inlet motor connector.

225

AIR CONDITIONING SYSTEM R 134.a

Checking the air conditioning system

Key.

T/P = Average temperature (°C ) at the air vents /

high pressure (Bars).

P = Low pressure (Bars).

Te = Exterior temperature (C° ).

HP = Pressure at compressor outlet (Bars).

BP = Pressure at compressor inlet (Bars).

TA = Average temperature (°C) of air blown from

the central vents.

C5HP18GD

226

Air Conditioning -> Checking the Efficiency of the Air Conditioning System for Your Citroen C3 SUV First Generation (2002-2009)

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