Get Air conditioning system -> 2.14.2 Pressures and temperatures in refrigerant circuit Guide for Volkswagen Touran 4 Door Second Generation (2015-2022)

Arteon 2018 ➤ , Atlas 2017 ➤ , CC 2012 ➤ , Caddy 2016 ➤ , Crafter 201 ...

Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Note

♦ All of the information and documents for analysis, processing

(or disposal) can be obtained from your gas processing / gas

disposal company.

♦ Included with the recycling cylinder is a form. Kindly fill this in

accordingly and attach it to the recycling cylinder.

♦ If it is not possible to weigh the recycling cylinder before and

after filling with contaminated refrigerant, the fill volume speci‐

fied for the vehicle in question can be quoted as the amount

of refrigerant that was filled in the recycling cylinder. This is

permissible as only the amount of refrigerant from a vehicle is

filled in a recycling cylinder.

– Move the insulated box -7- with recycling cylinder -1- and dry

ice to a secure, well ventilated area outside the building.

– Open the lid of the insulated box -7- or remove and allow the

dry ice to evaporate.

Note

Do not take the recycling cylinder -1- out of the insulated container

-7- until the dry ice has evaporated and the recycling cylinder has

adjusted to ambient temperature.

– Remove the recycling cylinder -1- from the insulated container

-7-.

– Take the recycling cylinder -1- to a suitable location for storage

until it is ready to be collected by the gas processing / gas

disposal company.

– Evacuate the refrigerant circuit with the air conditioner service

station for at least 1 hour

⇒ “2.5 Evacuating refrigerant circuit”, page 140 .

Note

♦ Subsequent evacuation results in the last remnants of conta‐

minated refrigerant, which could still be in the refrigerant oil,

being removed at an absolute pressure of less than 10 mbar.

♦ The next steps depend on the complaint with the refrigerant

circuit

⇒ “2.3 Performing gas analysis of refrigerant”, page 134 .

– Fill out the data sheet for the recycling cylinder (R-cylinder) if

the refrigerant is contaminated and firmly attach it to the recy‐

cling cylinder -1-.

Note

In the “Other comments” section, details can be provided regard‐

ing e.g. who is to receive the analysis results and in which way.

Example for recycling cylinder (R-cylinder) data sheet

2. Working with air conditioner service station

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Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Data sheet for R-cylinder if refrigerant is contaminated

Service contact

Dealership contact:

Email address:

Customer information:

Surname, first name:

Street:

Town/city:

Vehicle model

Identification

Vehicle identification

number:

Mileage:

Gas analysis performed

on:

Information about R-cylinder

Cylinder number:

Cylinder weight with

contents:

(gross weight)

Fill volume

(net weight)

Other comments

2.14

Checking pressures

⇒ “2.14.1 General information on checking pressures in the re‐

frigerant circuit”, page 170

⇒ “2.14.2 Pressures and temperatures in refrigerant circuit”, page

173

⇒ “2.14.3 Checking pressures in the refrigerant circuit with the

ignition switched off”, page 176

⇒ “2.14.4 Checking pressures with air conditioning system switch‐

ed on - vehicles with mechanical air conditioning compressor”,

page 183 .

⇒ “2.14.5 Checking pressures with air conditioning system switch‐

ed on - vehicles with electrical air conditioning compressor”, page

205

2.14.1

General information on checking pres‐

sures in the refrigerant circuit

Note

Work on the refrigerant circuit that involves the air conditioner

service station can usually be carried out without the need to de-

energise the high-voltage system.

170

Rep. gr.87 - Air conditioning system

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Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Vehicles with electrically-actuated valves in the refrigerant circuit

that are not open when de-energised:

Note

On vehicles with high-voltage system and auxiliary air condition‐

ing system functions (“heat pump mode” or “cooling of high-

voltage battery”), valves may be installed in the refrigerant circuit

that are not open when de-energised. These valves are opened

and closed e.g. via incremental motors and are no longer actu‐

ated when the ignition is switched off. To check the pressures in

the refrigerant circuit with the air conditioning system switched off,

however, no areas may be isolated, which is why these valves

must be opened before work is carried out ⇒ Heating, air condi‐

tioning; Rep. gr. 87 ; Refrigerant circuit; System overview -

refrigerant circuit and ⇒ Vehicle diagnostic tester in “Guided Fault

Finding” mode.

– Use the vehicle diagnostic tester to open the electrically-ac‐

tuated valves that are not open when de-energised ⇒ Vehicle

diagnostic tester in “Guided Fault Finding” mode.

All vehicles

NOTICE

Risk of damage to the air conditioner compressor or air condi‐

tioner service station.

Opening the valves with the air conditioning system switched

on can cause a short circuit between the high pressure and low

pressure side.

– Never open valves on the high pressure or low pressure side

with the air conditioning system switched on.

Note

♦ Certain conditions for testing are pertinent to a certain vehicle

and are described in the vehicle-specific workshop manual ⇒

Heating, air conditioning; Rep. gr. 00 ; Repair instructions;

Checking cooling output .

♦ Check the cooling output ⇒ Heating, air conditioning; Rep. gr.

00 ; Repair instructions; Checking cooling output (vehicle-spe‐

cific workshop manual).

♦ Connections with valve and service connections for measuring

and testing ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrig‐

erant circuit; System overview - refrigerant circuit (vehicle-

specific workshop manual)

♦ Depending on the version of air conditioner compressor, a

valve may be installed on the high-pressure side that prevents

liquefied refrigerant flowing back into the air conditioner com‐

pressor after the air conditioning system is switched off. If an

air conditioner compressor with this valve is installed in a ve‐

hicle with a refrigerant circuit with expansion valve, it could

take some time before the pressure on the high-pressure side

drops (the expansion valve is cold and the pressure on the

low-pressure side rises quickly after switching off, the expan‐

sion valve closes and refrigerant only flows slowly on the low-

pressure side). If the air conditioner compressor is switched

on, the pressure on the low-pressure side drops, the expan‐

sion valve opens and refrigerant can flow on the low-pressure

side.

2. Working with air conditioner service station

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Air conditioning systems with refrigerant R1234yf - General information - Edition 07.2017

Under certain operating conditions, residual moisture in the re‐

frigerant circuit may lead to the formation of ice at the air condi‐

tioner compressor regulating valve. The ice impairs the air

conditioner compressor control and causes the evaporator to be

cooled excessively and to ice up. Icing-up of the evaporator may

give rise to the following problems:

♦ Repeated or sporadic failure of the air conditioner (no cooling/

heat output) after a lengthy journey. After switching off the en‐

gine and waiting for a short period, operation of air conditioner

returns to normal.

♦ Misting up of the windows on the inside after a long journey;

the windows are initially not cleared even by pressing the De-

frost button; the air conditioner functions properly again after

a short delay following engine shut-off (or after switching off

the air conditioner).

Remedy:

– On vehicles with an air conditioner compressor with air con‐

ditioner compressor regulating valve - N280- , check the

measured value of the evaporator output temperature sender

- G263- (via the “Read measured values” function). If the

measured value of the sender is too low under the operating

conditions described by the customer (at an ambient temper‐

ature above 0°C, colder than 0°C for an extended period even

though the -N280- is currently not actuated) or too high (higher

than approx. 10°C, even though the air conditioning system is

functioning properly): the evaporator may ice up due to the

incorrect measured value ⇒ Vehicle diagnostic tester in “Gui‐

ded Fault Finding” mode - air conditioning system and ⇒

Heating, air conditioning; Rep. gr. 00 ; Repair instructions;

Checking cooling output (vehicle-specific workshop manual).

– On vehicles without evaporator output temperature sender -

G263- , use e.g. the footwell vent temperature sender - G192-

to check the outlet temperature with the temperature set to

“low” or “cold” for the driver and front passenger side with the

lowest setting (4 or 5 bars) for the fresh air blower speed, air

outlet in the footwell and fresh air mode under the operating

conditions described by the customer. If the measured value

of the sender is too low (with an ambient temperature higher

than 0°C, colder than 0°C for an extended period), the evap‐

orator could ice up due to the wrong measured value ⇒ Vehicle

diagnostic tester in “Guided Fault Finding” mode - air condi‐

tioning system.

– On vehicles with shut-off valves in the refrigerant circuit, check

the function and actuation of these valves ⇒ Vehicle diagnostic

tester in “Guided Fault Finding” mode - air conditioning sys‐

tem, ⇒ Heating, air conditioning; Rep. gr. 87 ; Refrigerant

circuit; System overview - refrigerant circuit and ⇒ Heating,

air conditioning; Rep. gr. 00 ; Repair instructions; Checking

cooling output (vehicle-specific workshop manual).

– Check the refrigerant line from the evaporator (or from the in‐

ner heat exchanger) and the air conditioner compressor (thick

pipe, low pressure side) with the engine running. If this line is

very icy when the complaint is encountered (a thin layer of ice

is acceptable), this is also evidence that the temperature in the

evaporator is too low ⇒ Heating, air conditioning; Rep. gr. 87 ;

Refrigerant circuit; System overview - refrigerant circuit (vehi‐

cle-specific workshop manual).

– Empty the refrigerant circuit, renew the receiver with dryer,

renew the reservoir with dryer or desiccant cartridge and then

evacuate the refrigerant circuit for at least 3 hours ⇒ Heating,

air conditioning; Rep. gr. 87 ; Refrigerant circuit; System over‐

view - refrigerant circuit (vehicle-specific workshop manual)

and ⇒ page 129 .

172

Rep. gr.87 - Air conditioning system

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Air conditioning system -> 2.14.2 Pressures and temperatures in refrigerant circuit for Your Volkswagen Touran 4 Door Second Generation (2015-2022)

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