Get Clearingrefrigerantcircuitofcontaminants -> 7.1 Blowing through refrigerant circuit... Guide for Volkswagen LT Van Second Generation (1996-2006)

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

Clearing refrigerant circuit of contam‐

inants

7.1

Blowing through refrigerant circuit with

compressed air and nitrogen

•

Use compressed air to force moisture and other contaminants

out of the refrigerant circuit and use nitrogen to force moisture

out of the refrigerant circuit.

The method of blowing through the refrigerant circuit with

compressed air and nitrogen often requires a lot more work

than purging with refrigerant R134a. When purging with re‐

frigerant R134a, cleaning of the components is considerably

better. It is therefore always best to purge the system in the

event of complaints (the method of blowing through should

only be selected for certain complaints and for individual com‐

ponents).

Only individual components are to be blown through if:

♦ There is no way of purging the refrigerant circuit with refriger‐

ant R134a.

♦ If there is dirt or contamination in individual components of the

refrigerant circuit.

♦ If during evacuation of a leak-tight refrigerant circuit the vac‐

uum display is not constant on gauge (moisture in the refrig‐

erant circuit, which generates vapour pressure).^lk

♦ If the refrigerant circuit has been left open for longer than nor‐

mally required for repairs (e.g. following an accident)

♦ Pressure and temperature measurements in the circuit indi‐

cate that there is moisture in the refrigerant circuit.

♦ The vehicle-specific repair manual ⇒ Heating, air conditioning

deems it necessary after replacement of certain components.

Note

♦ Blowing through the refrigerant circuit with compressed air and

nitrogen will not achieve the same degree of cleanliness as

purging with refrigerant R134a. When purging with refrigerant

R134a, the refrigerant oil is shifted and cleaning of the com‐

ponents is better ⇒ page 67 .

♦ When blowing through, a maximum working pressure of 15 bar

must not be exceeded (if necessary, use pressure limiter for

compressed air as well).

WARNING

♦ Nitrogen can escape from the bottle in an uncontrolled

way.

♦ Work only with pressure regulator for nitrogen bottles

(max. working pressure 15 bar).

♦ The gas mixture escaping from the components must be

collected with appropriate extraction equipment.

7. Clearing refrigerant circuit of contaminants

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

– Always blow through components opposite the direction of re‐

frigerant flow.

Compressed air and nitrogen cannot be blown through the re‐

strictor, expansion valve, air conditioner compressor, receiver or

reservoir.

– In cases where condensers have a drying agent cartridge in

the integrated receiver, this drying agent cartridge must be re‐

moved.

– First blow out soiling using compressed air and then dry com‐

ponents with nitrogen.

– Fit adapter for connection of pressure hose to refrigerant cir‐

cuit ⇒ page 86 and ⇒ Heating, air conditioning .

To prevent oil and moisture from the compressed air system

making its way into the refrigerant circuit, the following points must

be observed.

♦ The compressed air must be fed through a compressed air

cleaning unit to clean and dry it. Therefore, use compressed

air filter and dryer (included in items supplied with tools for

painting work) ⇒ Workshop equipment and Special tools cata‐

logue .

♦ If refrigerant pipes have threads or union nuts at connections,

use adapter - V.A.G 1785/1- to adapter - V.A.G 1785/8- to

connect to 5/8" - 18 UNF charging hose. These adapters can

be found in the adapter case for VW/Audi passenger vehicle

set - VAS 6338/1- and adapter case for commercial vehicle

set - VAS 6338/50- .

♦ On refrigerant pipes without thread or union nut on the con‐

nection, use adapter from adapter case for VW/Audi passen‐

ger vehicle set - VAS 6338/1- or adapter case for commercial

vehicle set - VAS 6338/50- or proprietary air gun with rubber

nozzle.

Note

♦ Always extract any escaping air and/or nitrogen from the com‐

ponents using appropriate local exhaust ventilation LEV (e.g.

workshop extraction system).

♦ Certain contaminants and old refrigerant oil cannot be shifted

from the refrigerant circuit at all with compressed air or if the

compressed air is insufficient. These contaminants can only

be removed by purging with refrigerant R134a ⇒ page 67 .

Rep. gr.00 - Technical data

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ...

Air conditioning system with refrigerant R134a - Edition 10.2014

7.1.1

Blowing out refrigerant circuit

Note

♦ On vehicles where no adapters fit the refrigerant pipes, blow

through individual components using an air gun, for example,

with rubber nozzle. When doing this, be particularly careful not

to damage the connections (do not crush or scratch them).

♦ The evaporator should be blown through from the connection

to the low-pressure side (large diameter), with the expansion

valve or restrictor removed.

♦ Always blow through components opposite the direction of re‐

frigerant flow.

♦ Examine the expansion valve; renew if dirty or corroded.

♦ If components bear dark, sticky deposits which cannot be re‐

moved with compressed air, renew these components.

♦ Thin, light grey deposits on the insides of refrigerant pipes do

not impair the function of the components.

♦ After blowing out the system, always renew the receiver or

reservoir and the restrictor. If the condenser has a dryer, re‐

new the dryer cartridge or dryer.

7.2

Purging (cleaning) refrigerant circuit

with refrigerant R134a

Vehicles with high-voltage system (hybrid vehicles)

Observe the additional warning instructions for working on vehi‐

cles with high-voltage system ⇒ Electrical system; Rep. gr. 93 ;

General warning instructions for work on the high-voltage sys‐

tem .

WARNING

Risk of injury due to unexpected engine start

When working on a high-voltage vehicle, switch off the ignition,

and deposit the ignition key somewhere outside the passenger

compartment.

WARNING

Handling high-voltage cables:

•

Do not support yourself or your tools on high-voltage ca‐

bles and their components --> risk of damage to the insu‐

lation.

•

High-voltage cables must not be extensively bent or

kinked --> risk of damage to the insulation.

The round high-voltage connectors are colour-coded with

a coloured ring on the outside and mechanically coded

with respective guide lugs. Always observe the coding

when connecting the round high-voltage connectors in or‐

der to prevent any mechanical damage to the high-voltage

connectors.

7. Clearing refrigerant circuit of contaminants

Clearingrefrigerantcircuitofcontaminants -> 7.1 Blowing through refrigerant circuit... for Your Volkswagen LT Van Second Generation (1996-2006)

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