Volkswagen Beetle 2012, Caddy 2004, Caddy 1997, Bora 1999, Caddy 2011 Workshop Manual

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Workshop Manual

Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , Caddy 1997 ➤ , Caddy 2004 ➤ , Caddy 2011 ➤ , Caddy Kasten/Kombi 1996 ➤ , Caddy Pickup 1997 ➤ , California 2004 ➤ , California 2010 ➤ , Caravelle 2004 ➤ , Caravelle 2010 ➤ , Crafter 2006 ➤ , Eos 2006 ➤ , Fox 2005 ➤ , Golf 1992 ➤ , Golf 1998 ➤ , Golf 2004 ➤ , Golf 2009 ➤ , Golf 2013 ➤ , Golf Cabriolet 2012 ➤ , Golf Plus 2005 ➤ , Golf Plus 2009 ➤ , Golf Sportsvan 2015 ➤ , Golf Variant 1998 ➤ , Golf Variant 2007 ➤ , Golf Variant 2010 ➤ , Golf Variant 2014 ➤ , Jetta 2005 ➤ , Jetta 2011 ➤ , LT 1997 ➤ , Lupo 1999 ➤ , Lupo 3L 1999 ➤ , Multivan 2004 ➤ , Multivan 2010 ➤ , New Beetle 1999 ➤ , New Beetle Cabrio 2003 ➤ , Passat 1994 ➤ , Passat 1997 ➤ , Passat 2006 ➤ , Passat 2011 ➤ , Passat 2015 ➤ , Passat (NMS - US) 2012 ➤ , Passat CC 2009 ➤ , Passat Variant 1997 ➤ , Passat Variant 2011 ➤ ,

Service Department. Technical Information

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Service

Passat Variant 2015 ➤ , Phaeton 2003 ➤ , Polo 1995 ➤ , Polo 2002 ➤ , Polo 2010 ➤ , Polo 2014 ➤ , Polo Classic 1996 ➤ , Polo KH IN 2010 ➤ , Polo KH IN 2015 ➤ , Polo KH MY 2014 ➤ , Polo KH MY 2015 ➤ , Polo Lim IN 2011 ➤ , Polo Lim MY 2014 ➤ , Polo Lim RUS 2011 ➤ , Polo Variant 1998 ➤ , Scirocco 2009 ➤ , Scirocco 2015 ➤ , Sharan 1996 ➤ , Sharan 2011 ➤ , Tiguan 2008 ➤ , Touareg 2003 ➤ , Touareg 2010 ➤ , Touareg 2015 ➤ , Touran 2003 ➤ , Transporter 1996 ➤ , Transporter 2003 ➤ , Transporter 2004 ➤ , Transporter 2010 ➤ , XL1 2015 ➤ , e-Golf 2014 ➤ , e-up! 2014 ➤ , up! 2012 ➤

Air conditioning system with refrigerant R134a

Edition 10.2014

Service Department. Technical Information

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Service

List of Workshop Manual Repair GroupsList of Workshop Manual Repair GroupsList of Workshop Manual Repair Groups

Re pa ir G ro up

00 - Technical data

Technical information should always be available to the foremen and mechanics, because their careful and constant adherence to the instructions is essential to ensure vehicle road-worthiness and safety. In addition, the normal basic safety precautions for working on motor vehicles must, as a matter of course, be observed.

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

Air conditioning system with refrigerant R134a - Edition 10.2014

Contents

00 - Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1 General notes on air conditioning systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 Additional information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 Basics of air conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1.4 Vapour pressure table for refrigerant R134a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

1.5 Refrigerant R134a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

1.6 Characteristics of refrigerant R134a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

1.7 Refrigerant machine oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1.8 Comfort . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.9 How air conditioning works . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1.10 General safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

1.11 Safety precautions for when working on vehicles with air conditioning and when handling

refrigerant R134a . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

1.12 Basics for working on refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

2 General information on refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.1 Refrigerant circuit components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

2.2 Design of refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.3 Evacuation and charging valves for quick-release couplings of air conditioner service station

on refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

2.4 Switch and sender in refrigerant circuit and related connections . . . . . . . . . . . . . . . . . . . . 27

2.5 Electrical components not installed in refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . 30

2.6 Pressures and temperatures in the refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.7 Refrigerant circuit with expansion valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

2.8 Refrigerant circuit with restrictor and reservoir . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

2.9 Test and measurement work that can be performed using a pressure gauge . . . . . . . . . . 36

2.10 Air conditioner service and recycling equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

2.11 Notes to repairs on refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

3 Statutory texts and instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.1 Statutes and regulations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

3.2 Recycling and refuse law . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

3.3 Converting R12 refrigerant circuits to R134a refrigerant circuits and repairing them

(retrofitting) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

3.4 Maintaining records on refrigerant . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

4 Refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4.1 Important repair notes on air conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

4.2 Retrofitting refrigerant circuit from R12 refrigerant to R134a refrigerant . . . . . . . . . . . . . . 46

5 Working with the air conditioner service station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

5.1 Important notes for working with the air conditioner service station . . . . . . . . . . . . . . . . . . 48

5.2 Connecting air conditioner service station for measuring and checking . . . . . . . . . . . . . . 48

5.3 Draining refrigerant circuit using air conditioner service station . . . . . . . . . . . . . . . . . . . . . . 49

5.4 Evacuating refrigerant circuit using air conditioner service station . . . . . . . . . . . . . . . . . . . . 50

5.5 Charging refrigerant circuit using air conditioner service station . . . . . . . . . . . . . . . . . . . . 51

5.6 Bringing air conditioning system into service after charging . . . . . . . . . . . . . . . . . . . . . . . . 52

5.7 Charging container in air conditioner service station with refrigerant . . . . . . . . . . . . . . . . . . 53

5.8 Draining air conditioner service station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

6 Detecting leaks in refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

6.1 Leak detection in refrigerant circuit using compressed air or nitrogen . . . . . . . . . . . . . . . . 56

6.2 Searching for leaks in refrigerant circuits using leak detector V.A.G 1796 . . . . . . . . . . . . 58

6.3 Detecting leaks in refrigerant circuit using leak detecting system VAS 6196 or leak detecting

system VAS 6201 or a later model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

7 Clearing refrigerant circuit of contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

7.1 Blowing through refrigerant circuit with compressed air and nitrogen . . . . . . . . . . . . . . . . 65

Contents i

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

7.2 Purging (cleaning) refrigerant circuit with refrigerant R134a . . . . . . . . . . . . . . . . . . . . . . . . 67

8 Complaints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

8.1 Possible complaints about refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

8.2 Smells from heater and air conditioner unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123

9 Connecting air conditioner service station . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

9.1 For vehicles that have connections on both low-pressure and high-pressure sides of

refrigerant circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 126

10 Checking pressures on vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127

10.1 Checking pressures in refrigerant circuit (using air conditioner service station) . . . . . . . . 127

10.2 Checking systems with a restrictor and collector (with internally regulated air conditioner

compressor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

10.3 Checking systems with an expansion valve and reservoir (with internally regulated air

conditioner compressor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135

10.4 Checking systems with an expansion valve and reservoir (without regulated air conditioner

compressor) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141

10.5 Checking systems with a restrictor and reservoir and air conditioner compressor regulating

valve N280 (with externally regulated air conditioner compressor) . . . . . . . . . . . . . . . . . . 143

10.6 Checking systems with an expansion valve, receiver and air conditioner compressor

regulating valve N280 (with externally regulated air conditioner compressor) . . . . . . . . . . 148

10.7 With expansion valve, receiver and electrical air conditioner compressor . . . . . . . . . . . . . . 158

11 Renewing components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159

11.1 In the event of leaking or damaged components (apart from the air conditioner compressor,

receiver or reservoir) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160

11.2 Renewing air conditioner compressor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 161

11.3 Renewing receiver or reservoir, and restrictor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

12 Testing equipment and tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

12.1 List of test equipment, tools and materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165

ii Contents

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

Air conditioning system with refrigerant R134a - Edition 10.2014

00 – Technical data

1 General notes on air conditioning

systems

(VRL007231; Edition 10.2014)

1.1 Introduction

This repair manual is intended to provide technicians and fitters with the basic knowledge required for performing trained work on these systems.

Note

♦

Successful completion of a training course such as AB160 or ST160 Air conditioning systems including "technical informa‐ tion" is required.

♦

This repair manual is a part of the training material.

It should also be available to the responsible supervisory author‐ ities upon request.

Caution

Non-authorised tools or materials (e.g. leak inhibitor additive) may cause damage or adversely influence the system.

Only tools and materials approved by the manufacturer may be used.

Use of non-approved tools or materials will render the warranty void.

1.2 Additional information

♦ Technical Service Handbook with measures for rectifying lat‐

est malfunctions.

♦ Workshop manual for service work specific to model ⇒ Heat‐

ing, air conditioning; Rep. gr. 87 .

♦ ⇒ Current flow diagrams, Electrical fault finding and Fitting lo‐

cations

♦ Self-study programme No. 208 is no longer up-to-date in some

sections. E.g. the statement “The receiver must be renewed each time the refrigerant circuit is opened”. The following con‐ ditions apply ⇒ page 159

♦ Video programs for staff training.

♦ Catalogue of special tools / workshop testing.

♦ Service Organisation Volume 1 Additional equipment.

♦ Workshop manual for air conditioning system with R12 refrig‐

erant (for vehicles that were manufactured up to model year

1993). This workshop manual is only available as a hard copy.

1. General notes on air conditioning systems 1

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

1.3 Basics of air conditioning

1.3.1 Physical basics:

The four known physical states of water also apply to air condi‐ tioning refrigerants.

1 - Gas (invisible)

2 - Vapour

3 - Liquid

4 - Solid

When water is heated in a container (heat absorption), the rising water vapour is visible. If the vapour is heated by further heat absorption, the visible vapour becomes invisible gas. This proc‐ ess is reversible. If heat is extracted from gaseous water, it changes first to vapour, then to water and finally to ice.

A - Heat absorption

B - Heat dissipation

1.3.2 Heat always flows from warmer to colder material

Every material consists of a mass of moving molecules. The fast moving molecules of a warmer material loose part of their energy to slower molecules possessing less heat. This slows down the molecules of the warmer material and accelerates those with less heat. This continues until the molecules in both materials are moving at the same speed. They have the same temperature, and no further exchange of heat occurs.

1.3.3 Pressure and boiling point

The boiling points given in the table below are always based on an atmospheric pressure of 1 bar. If the pressure on a liquid is changed, its boiling point changes also.

It is well known that, for example, the lower the pressure, the lower the temperature at which water boils.

The vapour pressure curves for water and for refrigerant R134a show that at constant pressure and falling temperature the vapour becomes liquid (in the condenser), and that when pressure drops, the refrigerant changes from liquid into the vapour state (evapo‐ rator).

2 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

Vapour pressure curve for water

A - Liquid

B - Gaseous

C - Vapour pressure curve for water

1 - Pressure on the liquid in bar (absolute)

2 - Temperature in °C

Vapour pressure curve for refrigerant R134a

A - Liquid

B - Gaseous

D - Vapour pressure curve for refrigerant R134a

1 - Pressure on the liquid in bar (absolute)

2 - Temperature in °C

1.4 Vapour pressure table for refrigerant R134a

The vapour pressure table for each refrigerant is published in the literature for refrigeration engineers. This table shows the vapour pressure exerted on the liquid column in the container for a given temperature of the container.

Since a characteristic vapour pressure table is known for every refrigerant, one can determine what refrigerant is present by measuring pressure and temperature.

Note

Absolute pressure means that 0 bar corresponds to an absolute vacuum. The normal ambient pressure (positive pressure) corre‐ sponds to 1 bar absolute pressure. On most pressure gauges, a reading of 0 bar corresponds to an absolute pressure of one bar (which is confirmed by the existence of a -1 bar marking beneath the 0 scale marking).

Temperature in °C Pressure in bar (positive pres‐

sure) R134a

-45 -0.61

-40 -0.49

-35 -0.34

-30 -0.16

-25 0.06

-20 0.32

-15 0.63

-10 1.00

-5 1.43 0 1.92

1. General notes on air conditioning systems 3

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

Temperature in °C Pressure in bar (positive pres‐

sure) R134a

5 2.49 10 3.13 15 3.90 20 4.70 25 5.63 30 6.70 35 7.83 40 9.10 45 10.54 50 12.11 55 13.83 60 15.72 65 17.79 70 20.05 75 22.52 80 25.21 85 28.14 90 31.34

1.5 Refrigerant R134a

Air conditioners in vehicles use the evaporation and condensation process. The system contains a liquid with a low boiling point, called the refrigerant.

The refrigerant used is tetrafluoroethane R134a, which boils at

-26.5°C with vapour pressure of 1 bar.

1.5.1 Physical data of refrigerant R134a

Chemical formula CH2F–CF3 or CF3–CH2F Chemical designation Tetrafluoroethane Boiling point at 1 bar -26.5℃ Freezing point -101.6℃ Critical temperature 100.6℃ Critical pressure 40.56 bar (technical) pressure

equates to 39.5 bar (standard) pressure

1.5.2 Critical point

Critical point (critical temperature and critical pressure) means the point above which there is no longer a surface of separation be‐ tween liquid and gas.

Above its critical point, a substance is always gaseous.

At temperatures below the critical point, all types of refrigerant contained within a pressure tank exhibit a liquid phase and a gas phase, so that there is a gas cushion above the liquid.

As long as there is gas in the pressure vessel alongside the liquid, the pressure depends directly on the ambient temperature

⇒ page 3 .

4 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

Note

Different types of refrigerants must not be mixed with each other. Only refrigerants specified for the respective air conditioning sys‐ tem may be used.

1.5.3 Environmental aspects of refrigerant R134a

♦ R134a is a fluorocarbon and contains no chlorine.

♦ R134a has a shorter atmospheric persistence than refrigerant

R12.

♦ R134a does not damage the ozone layer, the potential to re‐

duce the amount of ozone is zero.

♦ The Global Warming Potential (GWP) of R134a lies by ap‐

prox. 1430 (the GWP for carbon dioxide lies by 1).

♦ The contribution of R134a to the greenhouse effect is less by

a factor of 10 than that of refrigerant R12.

1.6 Characteristics of refrigerant R134a

1.6.1 Trade names and designations

Refrigerant R134a is currently available under the following trade designations:

♦ H-FKW 134a

♦ SUVA 134a

♦ KLEA 134a

Note

♦

Other trade designations may be used in other countries.

♦

Among the large selection of various refrigerants, only this one may be used for vehicles. The designations Frigen or Freon are trade names. They apply also to refrigerants which must not be used in vehicles.

1.6.2 Colour

Like water, the refrigerant is colourless both in the vapour state and the liquid state. Gases are invisible. Only the boundary layer between gas and liquid is visible. (Fluid level in indicator tube of charging cylinder for bubbles in sight glass.) Liquid refrigerant R134a may appear coloured (milky) in a sight glass. This cloudi‐ ness is caused by partially dissolved refrigerant oil and does not indicate a fault.

1.6.3 Vapour pressure

In an enclosed container that is not completely full, refrigerant evaporates as vapour at the surface in a quantity sufficient to form an equilibrium between vapour and liquid. This equilibrium de‐ velops under pressure and is often called vapour pressure. The vapour pressure is temperature-dependant ⇒ page 3 .

1. General notes on air conditioning systems 5

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

1.6.4 Physical properties of R134a

Because the vapour pressure curves of R134a and other refrig‐ erants are in part very similar, unique identification on the basis of pressure alone is not possible.

The air conditioner compressor used for R134a is lubricated with special synthetic refrigerator oils, such as PAG oils (polyalkylene glycol oils).

1.6.5 Effects on metal

In its pure state, refrigerant R134a is chemically stable and does not attack iron or aluminium.

However, impurities such as chlorine compounds in the refriger‐ ant do attack certain metals and plastics. This can lead to block‐ ages, leaks and deposits on the air conditioner compressor piston.

1.6.6 Critical temperature and critical pres‐ sure

Up to a gas pressure of 39.5 bar positive pressure (corresponding to a temperature of 101°C) the refrigerant R134a remains chem‐ ically stable; however, above this temperature the refrigerant decomposes (see Combustibility).

1.6.7 Water content

Only very small amounts of water are soluble in liquid refrigerant. On the other hand, refrigerant vapour and water vapour mix in any proportion.

Any water present in the refrigerant circuit will be carried along as droplets. The dryer, dryer bag or dryer cartridge in the receiver or reservoir are capable of holding approx. 7 grams of water before they are full and cannot absorb any more water. If there is further water in the circuit, it will flow to the expansion valve jet or to the restrictor and becomes ice.

The air conditioning system will stop cooling.

Water destroys the air conditioner because at high pressures and temperatures it combines with other impurities to form acids.

1.6.8 Combustibility

Refrigerant is non-flammable. On the contrary, it has a fire-inhib‐ iting or fire-extinguishing effect. Refrigerant decomposes when exposed to flames or incandescent surfaces. UV light can also decompose refrigerants (UV is emitted by electric arc welding). Products of this decomposition are poisonous and must not be inhaled. However, these chemicals irritate the mucous mem‐ branes, giving adequate warning of their presence.

1.6.9 Charge factor

There must be space both for liquid and vapour in a container. As the temperature rises, the liquid expands. The space occupied by the vapour becomes smaller. Eventually, there will only be liquid in the container. After that time, even a small increase in temper‐ ature will result in a very large increase in pressure, since the liquid is seeking to expand further but there is no space for it to do so. The resulting forces are sufficient to burst the container. To prevent containers from being overcharged, regulations gov‐ erning the storage of compressed gases specify how many kilo‐ grams may be charged into a container for every litre of container volume. This charge factor multiplied by the internal volume gives the permissible charge quantity. The charge factor for the refrig‐ erants used in cars is 1.15 kg/l.

6 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

1.6.10 Detecting leaks

External damage can cause leaks in the refrigerant circuit. Be‐ cause a small leak will involve only small quantities of refrigerant, leaks should be checked for using an electronic leak detector or by introducing a leak detection additive to the refrigerant circuit. Electronic leak detectors can detect leakage rates of less than 5 grams loss of refrigerant per year. The leak detector should be specific to the composition of the particular refrigerant in use. For example, a leak detector for R12 refrigerant is not appropriate for R134a refrigerant because R134a refrigerant has no chlorine atoms to which the lead detector responds.)

1.7 Refrigerant machine oil

Refrigerant machine oil is miscible (approx. 20%–40% depending on the type of air conditioner compressor and the quantity of re‐ frigerant) in the refrigerant. It circulates continuously in the circuit and lubricates the moving parts.

Special synthetic refrigerant machine oils such as polyalkylene glycol (PAG) oil are used in conjunction with R134a air condition‐ ing systems. This is necessary because ordinary mineral oils are immiscible in R134a. In addition the materials of the R134a air conditioning system could be attacked if the mixture circulated within the refrigerant circuit under pressure and at high tempera‐ tures, or the lubricant film in the air conditioner compressor broke down. The use of unapproved oils can lead to the failure of the air conditioning system, so only approved oils must be used.

⇒ Parts catalogue

Type of oil for R134a in cars: PAG

1. General notes on air conditioning systems 7

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

Note

♦

Do not store refrigerant machine oils open to the atmosphere since they are very hygroscopic (they readily absorb water).

♦

Always keep oil containers tightly sealed.

♦

Do not reuse used refrigerant machine oil.

♦

Disposing of used oil: Volkswagen InfoNet; Operation; Man‐ uals and dealership documentation; Service handbook;

15. Environmental Protection; Follow link “Environmental pro‐ tection in the dealership and in the workshop” in "General notes"; 4. Waste disposal; 6. Disposal channels; g. Disposal of used oil; Refrigerant oils

♦

Used refrigerant machine oils from systems with halogenated hydrocarbons (at least one hydrogen atom has been replaced by e.g the halogens fluorine, chlorine, bromine or iodine) must be disposed of as waste requiring particular care. It is imper‐ missible to mix such oils with other oils or materials. Proper storage and disposal must be performed according to guide‐ lines in the country where the work is being performed. Ob‐ serve, for example in the Federal Republic of Germany, the climate protective regulation concerning chemicals; closed substance cycle waste management and ensuring environ‐ mentally compatible waste disposal (in other countries other statutes and regulations may apply)

♦

Reference sources for technical rules and safety at work / ac‐ cident prevention for the Federal Republic of Germany

♦

Sources in other countries may be obtained from the respon‐ sible authorities

♦

Ester-based oils are suitable only for larger systems (not for air conditioning systems in cars).

1.7.1 Properties of refrigerant oils

The most important properties are high solubility in refrigerants, good lubrication characteristics, freedom from acid and very low water content. For this reason, only certain oils may be used. A list of approved refrigerant oils and quantities can be found in the vehicle-specific workshop manuals in ⇒ Rep. gr. 00 or ⇒ Rep. gr. 87 .

The PAG oils suitable for refrigerant R134a are strongly hygro‐ scopic and are immiscible with other oils. Therefore, opened containers should be closed again immediately to protect them from moisture. Refrigerant oils age under the influence of mois‐ ture and acids; they become dark, viscous and aggressive to‐ wards metals.

Note

♦

For refrigerant circuits with refrigerant R134a, use only the oil approved for the air conditioner compressor. See ⇒ Rep. gr. 00 or ⇒ Rep. gr. 87 in the repair manual for the specific ve‐ hicle.

♦

Disposing of used oil: Volkswagen InfoNet; Operation; Man‐ uals and dealership documentation; Service handbook;

15. Environmental Protection; Follow link “Environmental pro‐ tection in the dealership and in the workshop” in "General notes"; 4. Waste disposal; 6. Disposal channels; g. Disposal of used oil; Refrigerant oils

8 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

1.8 Comfort

A basic requirement for concentrated and safe driving is the feel‐ ing of comfort in the passenger compartment. Especially when it is hot and humid, comfort can be attained only through the use of air conditioning. Of course, open windows, an open sunroof or increased air ventilation can contribute to comfort, but they all have certain disadvantages within the vehicle interior, such as additional noise, draughts, exhaust gases, unfiltered entry of pol‐ len (unpleasant for allergy sufferers).

A well regulated air conditioning system in conjunction with a well thought-out heating and ventilation system can create a feeling of well-being and comfort by regulating the interior temperature, humidity and rate of air change, regardless of the external con‐ ditions. This must be available whether the vehicle is moving or not.

Other important advantages of air conditioning are

♦ The cleansing of the air directed into the passenger compart‐

ment. (Dust and pollen, for example, are washed out by the moist fins of the evaporator and carried off with the conden‐ sation water.)

♦ Temperatures in a mid-range car (for example, after a short

period of driving, ambient temperature 30°C in the shade and the vehicle in direct sunlight).

Head region 23℃ 42℃ Chest region 24℃ 40℃ Footwell 30℃ 35℃

1.8.1 Environmental aspects

Since about 1992, the air conditioning systems of newly manu‐ factured cars have been successively changed to refrigerant R134a. This refrigerant contains no chlorine and thus does not damage the ozone layer.

Up until about 1992, air conditioning systems were charged with refrigerant R12. Due to its chlorine atoms, this CFC has a high potential for destroying ozone and, in addition, a potential for in‐ creasing the greenhouse effect.

There are programs for exchanging old air conditioning systems containing the ozone-damaging refrigerant R12.

⇒ Repair manual for air conditioning systems with refrigerant R12 . This workshop manual is only available as a hard copy.

To protect the environment, no refrigerant should be released into the atmosphere ⇒ page 39 (statutory texts and instructions).

1.9 How air conditioning works

The temperature in the passenger compartment depends on the

With air conditioning

system

amount of heat radiated through the windows and conducted by the metal parts of the body. In order to maintain comfortable tem‐ peratures for the occupants on very warm days, part of the available heat must be pumped away.

Since heat spreads towards cooler bodies, a unit that can create low temperatures is fitted in the vehicle interior. Refrigerant is constantly being evaporated in it. The latent heat of evaporation is taken from the air passing through the evaporator.

The refrigerant carries the heat with it as it is pumped away by the air conditioner compressor. The work performed by the air con‐

Without air condi‐

tioning system

1. General notes on air conditioning systems 9

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

ditioner compressor on the refrigerant increases its heat content and its temperature. Its temperature is now considerably higher than that of the ambient air.

The hot refrigerant flows with its heat content to the condenser. There the refrigerant looses its heat through the condenser to the surrounding air due to the temperature gradient between the re‐ frigerant and the surrounding air.

Thus, the refrigerant is a means of heat transport. Because it will be needed again, it returns to the evaporator.

All air conditioning systems basically depend on the circulation of refrigerant. However, there are differences in the construction of the system.

1.10 General safety

♦ In accordance with VBG 20, the Federation of Employers Li‐

ability Insurance Associations.

♦ Observe instructions specific to the workplace; ⇒ Volkswagen

ServiceNet; Handbooks; Service handbook; Environmental protection . Refrigerant from air conditioning systems / refrig‐ erant oils - to be displayed at refrigerant designated working area.

1.10.1 Product characteristics

Refrigerants used in car air conditioning systems belong to the new generation of refrigerants, the chlorine-free, partially-fluori‐ dated hydrocarbons (H-CFC, R134a).

In regard to their physical behaviour, they are refrigerants which can be liquefied under pressure. They are subject to Regulations for Pressure Tanks and may be charged only into approved and identified pressurised gas containers.

Specific conditions which apply for safe and proper use must be maintained.

1.10.2 Handling refrigerants

WARNING

Danger of freezing injuries.

The refrigerant can emerge as liquid or as vapour.

Do not open containers in which this refrigerant is present.

If refrigerant containers are opened, the contents may escape in liquid or vapour form. The higher the pressure in the container, the more energetic the emergence will be.

How high the pressure is depends on two factors:

• What type of refrigerant is in the container. “This is because

the lower the boiling point, the higher the pressure.”

• How high the temperature is. “This is because the higher the

temperature, the higher the pressure.”

1.10.3 Wear protective glasses

Put on protective glasses. This will prevent the refrigerant enter‐ ing the eyes, which in certain circumstances can cause severe injury due to frostbite.

10 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

1.10.4 Wear protective gloves and apron

Refrigerants dissolve fats and oils very well. Therefore, when they come in contact with the skin, they take away the protective layer of fat. Skin from which the natural oil and fat have been removed is vulnerable to cold and germs.

Note

contact with the skin

systems

1.10.5 Do not allow liquid refrigerant to come in

The refrigerant will draw its latent heat of evaporation from its surroundings. That can be your skin. This can result in very low temperatures. The result is local frostbite (boiling point of R134a is -26.5°C at normal atmospheric pressure).

1.10.6 Do not breath in refrigerant vapour

In high concentrations, emerging refrigerant vapours can mix with the air and displace the oxygen necessary for breathing.

1.10.7 Absolutely NO SMOKING

Refrigerant can decompose in a burning cigarette. The resulting substances are poisonous and must not be breathed in.

1.10.8 Welding and soldering on refrigeration

Before welding and brazing on vehicles (in the vicinity of the air conditioning system components), extract the refrigerant and then purge the system by blowing through with compressed air and using nitrogen.

The products of decomposition of refrigerants under heat are not only poisonous but are strongly corrosive, so that pipework and system parts could be attacked. This refers primarily to hydrogen fluoride.

1.10.9 Pungent smell

A pungent odour indicates that the products of decomposition mentioned above are already present. Breathing in these sub‐ stances must be avoided under all circumstances, or the bron‐ chial tubes, lungs and other organs could be injured.

1.10.10 First aid

• In the event of contact with the eyes or mucous membranes, wash immediately with copious running water and summon an eye specialist.

• In the event of contact with the skin, remove wetted clothing and wash the affected skin with copious water.

• If refrigerant vapours are breathed in high concentrations, take the patient immediately into the fresh air. Summon a doctor. If the patient has trouble breathing, administer oxygen. If the patient's breathing is restricted or stops, bend the head at the neck and commence resuscitation.

1.10.11 Handling pressure tanks

• Secure vessels against falling over!

Secure standing cylinders against falling over and lying cylinders from rolling away.

1. General notes on air conditioning systems 11

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

• Do not throw pressure vessels!

When falling, the containers may become severely deformed so that they may be torn open. The refrigerant evaporates immedi‐ ately, releasing violent forces. Flying fragments of cylinders can cause severe injuries.

Bottle valves can brake during improper transport. To protect cyl‐ inder valves, bottles may be transported only with protective covers screwed on.

• Do not place near radiators!

High temperatures can occur near radiators. Higher temperatures however also mean higher pressures, which may exceed the rat‐ ed pressure of the vessel.

1.10.12 Do not heat above 50°C

To prevent danger, the Regulations for Pressure Tanks provide that tanks shall not be heated to more than 50°C.

1.10.13 Do not apply uncontrolled heat

Do not heat with an open flame under any circumstance. The local overheating that will result can change the structure of the con‐ tainer's materials, thereby reducing the safe maximum pressure limit of the container. In addition, the danger arises that the re‐ frigerant decomposes due to localised overheating.

1.10.14 Seal empty containers

Empty refrigerant containers must in all cases be sealed so as to prevent intrusion of moisture. Moisture causes steel containers to rust. This weakens the walls of the containers. In addition, rust particles which enter the refrigerant system from the container cause malfunctions.

1.10.15 Safety instructions for using extraction and charging equipment

• Before connecting the charging system to the air conditioning

system, make sure that all existing shut-off valves are closed.

• Before the charging equipment is decoupled from the air con‐

ditioning system, ensure that the process has finished. The reason for this is to ensure that no refrigerant oil escapes into the atmosphere.

• After the cleaned refrigerant from the charging system has

been charged into an external pressurised gas cylinder, close the hand shut-off valves on the bottle and the charging system.

• Do not expose charging system to moisture or use it in a wet

environment.

• Before performing service work and the charging system, dis‐

connect the current supply.

• To reduce danger of fire, avoid using extension cords. If nev‐

ertheless it is necessary to use an extension cable, use an extension cable with a cross-section of at least 2.5 mm2.

• In case of fire, remove external cylinder.

• If entrained oil from the air conditioning system suction accu‐

mulator is trapped in the measuring beaker supplied, be sure subsequently to pour the oil into a container that can be sealed, since the oil contains a small amount of refrigerant. Refrigerants must not be released into the environment.

• When the air conditioner service station is switched off, it must

be secured against rolling away.

12 Rep. gr.00 - Technical data

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

1.11 Safety precautions for when working on

Air conditioning service station - VAS 6007A- (and further service stations currently available)

⇒ Workshop equipment

♦ It is recommended that a bottle containing water be kept

♦ Should liquid refrigerant get into the eyes, thoroughly

♦ The doctor must be informed that the frostbite has been

♦ Work on the air conditioning system refrigerant circuit in

♦ Refrigerant must not be stored in low-lying rooms (e.g.

vehicles with air conditioning and when handling refrigerant R134a

WARNING

at hand for purging out the eyes.

purge the eyes with water for about 15 minutes. Then ad‐ minister eye drops and visit a doctor immediately even if the eyes do not hurt.

caused by refrigerant R134a. If, in spite of these safety measures, refrigerant comes into contact with other body parts, these areas must also be immediately purge with cold water for at least 15 minutes.

well ventilated rooms only. Switch on exhaust gas fume extractor (if there is one).

Air conditioning system with refrigerant R134a - Edition 10.2014

cellars) or their stairways or window shafts.

• Do not weld, braze or soft-solder any parts of the charged air conditioning system. This also applies to welding and solder‐ ing work on the vehicle when the danger exists that parts of the air conditioning system may heat up. During painting op‐ erations, temperatures of objects in the drying oven or in its pre-heating zone must not exceed 80°C.

Reason:

Heating causes great excess pressure to develop in the system, which can cause the pressure release valve of the system to open.

Precautions:

– Use the air conditioner service station to evacuate the refrig‐

erant circuit.

Note

Damaged or leaking components of the air conditioning system must not be repaired by welding or soldering. They must always be renewed.

Refrigerant containers (e.g. charging cylinders of air conditioner service station) must never be subjected to excessive heat or ex‐ posed to direct sunlight.

Precautions:

– Never charge a container completely with liquid refrigerant.

Without sufficient expansion space (gas cushion), the con‐ tainer will burst should the temperature rise, with devastating consequences ⇒ page 5 .

1. General notes on air conditioning systems 13

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

Under no circumstances may refrigerant be charged into systems or vessels containing air.

Precautions:

– Evacuate systems and containers before charging with refrig‐

erant.

1.12 Basics for working on refrigerant circuit

• Observe instructions specific to the workplace; ⇒ Volkswagen ServiceNet; Handbooks; Service handbook; Environmental protection . Refrigerant from air conditioning systems / refrig‐ erant oils - to be displayed at refrigerant designated working area.

• Observe the utmost cleanliness when working.

• When handling refrigerants and nitrogen, wear protective clothing, protective glasses and protective gloves.

• Switch on exhaust gas fume extractor (if there is one).

• Extract the refrigerant circuit using only the air conditioner service station, and only then loosen the threaded joints and renew the defective components.

• Protect units and hoses against moisture and dirt using sealing caps.

• Use only tools and materials that are intended for use with refrigerant R134a.

• Protect refrigerant oil by sealing container to prevent ingress of moisture.

– Blow through refrigerant circuit with compressed air and nitro‐

gen ⇒ page 65 :

– Purge refrigerant circuit with refrigerant R134a. ⇒ page 67

In vehicles that have an air conditioner compressor without a magnetic clutch:

14 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

Note

♦

If the engine is being started for the first time after the refrig‐ erant circuit has been reassembled.

♦

If possible, start engine only with refrigerant circuit charged.

♦

The air conditioner compressor is driven permanently by the poly V-belt pulley or elastic drive coupling (it is not fitted with a magnetic clutch).

♦

If an air conditioner compressor seizes, the overload protec‐ tion separates from the air conditioner compressor shaft. Even if no bulges are visible in the V-belt pulley or overload protec‐ tion, it may be that the air conditioner compressor has seized. Another indication is abraded rubber material around the poly V-belt pulley or overload protection.

♦

The air conditioner compressor has an internal oil circuit to ensure that the air conditioner compressor is not damaged when the refrigerant circuit is empty. This means that about

40 to 50 cm3 refrigerant oil remain in the air conditioner com‐ pressor.

♦

The engine may be started only when the refrigerant circuit is properly assembled. If, for example, the refrigerant lines are not connected to the air conditioner compressor and the en‐ gine is running, the compressor may heat up so much through internal warming that it will be destroyed.

♦

The air conditioner compressor regulating valve - N280- is not activated when the refrigerant circuit is empty and the air con‐ ditioner compressor idles with the engine.

♦

If it is necessary to start engine with an empty refrigerant cir‐ cuit:

♦

The refrigerant circuit must be fully assembled.

♦

At least ¼ of the quantity of refrigerant oil specified for this refrigerant circuit must be in the air conditioner compressor.

♦

The engine speed must not exceed 2000 rpm.

♦

The engine should run < 10 minutes.

1.12.1 O-ring

♦ Use only O-rings that are resistant to refrigerant R134a and

related refrigerant oils. O-rings are no longer colour-coded. Coloured and black O-rings are used.

♦ Check that the O-rings used have the correct internal diame‐

ters.

⇒ Rep. gr. 87

⇒ Parts catalogue

♦ Never reuse O-rings.

♦ Before installing, moisten O-rings lightly with refrigerant oil

(PAG oil).

1. General notes on air conditioning systems 15

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

Note

♦

When purging components with compressed air and nitrogen, always collect the gas mixture exiting the component with suit‐ able exhaust gas extraction equipment (workshop fume ex‐ tractor).

♦

After completing repair work, screw sealing caps (with seals) onto valve and service connections.

Before operating the air conditioning system. Check the vehiclespecific charge quantities ⇒ Rep. gr. 87 .

Do not top up a charged refrigerant circuit; discharge refrigerant present and recharge system.

1.12.2 Before operating the air conditioning

system after recharging with refrigerant

– After installing a new air conditioner compressor or filling with

fresh refrigerant oil (e.g. after blowing out refrigerant circuit), turn compressor pulley 10 revolutions by hand before starting engine. This will prevent damage to the air conditioner com‐ pressor.

– On 5-cyl. or 10-cyl. diesel engine, turn air conditioner com‐

pressor at overload protection 10 times by hand. Then install compressor. This will prevent damage to the air conditioner compressor.

– Start the engine with the air conditioning system switched off

(the air conditioning system magnetic clutch - N25- and the air conditioner compressor regulating valve - N280- are not acti‐ vated).

– After the engine has stabilised at its idling speed, switch on

the air conditioner compressor and allow the engine to idle for at least 10 minutes at maximum cooling power.

16 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

2 General information on refrigerant

circuit

2.1 Refrigerant circuit components

Caution

Non-authorised tools or materials (e.g. leak inhibitor additive) may cause damage or adversely influence the system.

Only tools and materials approved by the manufacturer may be used.

Use of non-approved tools or materials will render the warranty void.

• All components of the refrigerant circuit that were submitted for quality monitoring must always be sealed (use the original sealing caps from the genuine part).

• Renew damaged or leaky components of the refrigerant circuit

⇒ page 159 .

• The genuine parts (air conditioner compressor, reservoir, re‐ ceiver, evaporator and condenser) are charged with nitrogen before shipment. This filling is being gradually discontinued. Therefore, when the sealing plugs are unscrewed from the genuine part little or no pressure equalisation is noticeable.

2.1.1 Distribution of the refrigerant circuit

components and their influence on the high-pressure and low-pressure sides

On the high-pressure side, there are the condenser, the receiver and the restrictor or expansion valve that acts as the separation between the high-pressure fluid and low-pressure fluid sides.

High pressure is created because the restrictor or expansion valve forms a restriction and holds back the refrigerant, leading to increased pressure and temperature.

Excessive pressure results if the circuit is filled with too much re‐ frigerant or refrigerant oil, or the condenser is dirty, the radiator fan is defective, there is a blockage in the system or there is moisture in the refrigerant circuit (causing the restrictor or expan‐ sion valve to ice up).

On the low-pressure side, there are the evaporator, the reservoir, the temperature sensor for the evaporator and the air conditioner compressor that acts as the separation between the high-pres‐ sure and low-pressure gas sides.

A loss of pressure in the system can be due to loss of refrigerant, restrictor or expansion valve failure (not creating a restriction), defective air conditioner compressor or an iced-up evaporator.

2. General information on refrigerant circuit 17

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

2.1.2 Air conditioning system compressor with magnetic clutch:

The air conditioner compressor is driven by a V-belt from the en‐ gine.

An electromagnetic clutch is fitted to the air conditioner compres‐ sor. When the air conditioning system is switched on, it transmits the mechanical drive between the V-belt pulley and the air con‐ ditioner compressor drive shaft.

A fusible link is incorporated in the air conditioner compressor Vbelt pulley. In the event of stiffness in the air conditioner com‐ pressor, it trips the electromagnetic clutch and protects the V-belt drive from overload.

The air conditioner compressor draws refrigerant gas from the evaporator, compresses it and sends it to the condenser.

Note

♦

The air conditioner compressor contains refrigerant oil, which can be mixed with R134a refrigerant at any temperature.

♦

The maker's nameplate states the refrigerant for which the air conditioner compressor is suitable. A valve regulates the pres‐ sure on the low-pressure side within the specified range (reg‐ ulation characteristic).

♦

So that the air conditioner compressor suffers no damage when the refrigerant circuit is empty, the magnetic clutch is disconnected and the regulating valve for the air conditioner compressor - N280- is no longer activated (the air conditioner compressor idles with the engine).

18 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

2.1.3 Air conditioner compressor without magnetic clutch

The air conditioner compressor is driven by a V-belt from the en‐ gine.

A shear link is incorporated in the air conditioner compressor Vbelt pulley. In the event of stiffness in the air conditioner com‐ pressor, it shears off and protects the V-belt drive from overload.

The air conditioner compressor draws refrigerant gas from the evaporator, compresses it and sends it to the condenser.

Note

♦

The air conditioner compressor contains refrigerant oil, which is miscible with R134a refrigerant at all temperatures.

♦

The maker's nameplate states the refrigerant for which the air conditioner compressor is suitable. A valve regulates the pres‐ sure on the low-pressure side within the specified range (reg‐ ulation characteristic).

♦

The regulating valve for this air conditioner compressor is ex‐ ternally activated.

♦

The engine should be started only when the refrigerant circuit has been fully assembled ⇒ page 14 .

♦

The air conditioner compressor has an internal oil circuit to ensure that the air conditioner compressor is not damaged when the refrigerant circuit is empty. This means that about

40 to 50 cm3 refrigerant oil remain in the air conditioner com‐ pressor.

2. General information on refrigerant circuit 19

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

2.1.4 Air conditioner compressor without magnetic clutch, with elastic drive cou‐ pling

The air conditioner compressor is driven directly by the power steering vane pump.

There is an overload protection on the drive shaft of the air con‐ ditioner compressor, which shears in the event of the air condi‐ tioner compressor seizing, thus permitting the power steering vane pump to remain operational.

The air conditioner compressor draws refrigerant gas from the evaporator, compresses it and sends it to the condenser.

Note

♦

The air conditioner compressor contains refrigerant oil, which is miscible with R134a refrigerant at all temperatures.

♦

The maker's nameplate states the refrigerant for which the air conditioner compressor is suitable. A valve regulates the pres‐ sure on the low-pressure side within the specified range (reg‐ ulation characteristic).

The regulating valve for this air conditioner compressor is ex‐ ternally activated.

The engine should be started only when the refrigerant circuit has been fully assembled ⇒ page 14 .

The air conditioner compressor has an internal oil circuit to ensure that the air conditioner compressor is not damaged when the refrigerant circuit is empty. This means that about

40 to 50 cm3 refrigerant oil remain in the air conditioner com‐ pressor.

2.1.5 Electrical air conditioner compressor for high-voltage system

WARNING

♦ High voltage on high-voltage system of hybrid vehicle!

Health risks for persons wearing medical devices!

♦ Following procedure also requires work on high-voltage

system. All work on vehicles with a high-voltage system may only be done by trained electricians. Work must be advised by a high-voltage technician.

♦ Observe the general warning instructions for work on the

high-voltage system ⇒ Electric drive, Repair group 93; General warning instructions for work on the high-voltage system.

♦ Now, ensure there is no voltage in high-voltage system ⇒

Electric drive, Repair group 93; Ensuring there is no volt‐ age in high-voltage system.

20 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

WARNING

The electrical air conditioner compressor requires a different refrigerant oil!

For capacities, see workshop manual for specific vehicle.

Electrical air conditioner compressor

WARNING

Danger of short circuit

The air conditioner compressor operates with 288 volts and at a speed range of 800 to 8,600 rpm.

Do not touch air conditioner compressor when drive units are starting. Danger of short circuit!

The air conditioner compressor draws refrigerant gas from the evaporator, compresses it and sends it to the condenser.

Note

♦

The air conditioner compressor contains refrigerant oil, which is miscible with R134a refrigerant at all temperatures.

♦

The maker's nameplate states the refrigerant for which the air conditioner compressor is suitable. The flow rate is controlled via the engine speed.

♦

The engine should be started only when the refrigerant circuit has been fully assembled ⇒ page 14 .

♦

The air conditioner compressor has an internal oil circuit to ensure that the air conditioner compressor is not damaged when the refrigerant circuit is empty. This means that about

40 to 50 cm3 refrigerant oil remain in the air conditioner com‐ pressor.

♦

The air conditioner has a pressure relief valve.

2.1.6 Condenser

The condenser transfers heat from the compressed refrigerant gas to the surrounding air.

This allows the refrigerant gas to condense into liquid form.

2. General information on refrigerant circuit 21

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

2.1.7 Evaporator

The liquid refrigerant evaporates in the tubes of the evaporator. The latent heat of evaporation is taken from the air streaming past the evaporator fins. The air cools. The refrigerant evaporates and is drawn into the air conditioning system compressor carrying with it the heat it has absorbed.

A restrictor or an expansion valve allows a defined quantity of refrigerant to flow to the evaporator. In systems with an expansion valve, the flow is regulated such that only gaseous refrigerant ex‐ its the evaporator.

2.1.8 Reservoir

The reservoir collects the vaporised and gaseous mixture coming from the evaporator to ensure the air conditioner compressor re‐ ceives only gaseous refrigerant. Gaseous refrigerant is formed from the vapour.

Refrigerant oil flowing in the circuit does not remain in the reser‐ voir, as an oil extraction hole has been provided.

Moisture which has entered the refrigerant circuit during repairs will be collected by a filter (dryer bag) in the reservoir.

Gaseous refrigerant with oil is drawn in by the air conditioner compressor.

Note

♦

Renew the reservoir if the refrigerant circuit has stood open for any length of time (more than the normal repair time) and moisture has entered the system, or if it is required because of a specific complaint ⇒ page 159 .

Do not remove sealing plugs -A- and -B- until just before in‐ stallation.

♦

The dryer bag in an unsealed reservoir will become saturated with moisture within a short time and is then unusable.

♦

When installing, observe arrow indicating direction of flow, if applicable.

22 Rep. gr.00 - Technical data

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

Air conditioning system with refrigerant R134a - Edition 10.2014

2.1.9 Restrictor

The restrictor creates a restriction. This restriction limits the flow, separating the high-pressure and low-pressure sides in the re‐ frigerant circuit. Upstream of the restrictor, the refrigerant is warm due to the high pressure. Downstream of the restrictor, the refrig‐ erant is cold due to the low pressure. Upstream of the narrow point is a strainer to catch dirt and downstream of the narrow point is a strainer to atomise the refrigerant before it enters the evaporator.

Note

♦

Arrow -A- on the restrictor points to the evaporator.

♦

Renew it every time the refrigerant circuit is opened.

♦

Observe different versions.

⇒ Rep. gr. 87

⇒ Parts catalogue

2.1.10 Receiver

The receiver collects the liquid droplets and directs them in a continuous stream to the expansion valve. Moisture which has entered the refrigerant circuit during assembly is collected by the dryer bag in the receiver.

Note

♦

Renew the receiver if the refrigerant circuit has stood open for any length of time (more than the normal repair time) and moisture has entered the system, or if it is required because of a specific complaint ⇒ page 159 .

♦

Do not remove sealing plugs until just before installation.

♦

The dryer bag in an unsealed receiver will become saturated with moisture within a short time and is then unusable.

♦

When installing, observe arrow indicating direction of flow, if applicable.

The new generation of receivers are mounted directly on the con‐ denser and contain a dryer cartridge.

Note

♦

Renew the dryer cartridge if the refrigerant circuit has stood open for any length of time (more than the normal repair time) and moisture has entered the system, or if it is required be‐ cause of a specific complaint ⇒ page 159 .

♦

Remove the dryer cartridge from its packaging only immedi‐ ately before installing it.

♦

A dryer cartridge in unsealed packaging will become saturated with moisture within a short time and is then unusable.

2. General information on refrigerant circuit 23

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Amarok 2011 ➤ , Beetle 2012 ➤ , Bora 1999 ➤ , CC 2010 ➤ , CC 2012 ➤ , ... Air conditioning system with refrigerant R134a - Edition 10.2014

2.1.11 Expansion valve

The expansion valve atomises incoming refrigerant and regulates the flow so that, depending on the heat transport, the vapour does not become a gas until it reaches the outlet of the evaporator.

2.1.12 O-ring

These O-rings seal the joints between the individual components of the refrigerant circuit.

Use only seals that are resistant to refrigerant R134a and its as‐ sociated refrigerant oils. This is assured by using genuine re‐ placement parts.

⇒ Parts catalogue

O-ring:

• Never reuse seals!

• Check that diameters -a- and -b- are correct.

• Before fitting a seal, coat it lightly with refrigerant oil.

Note

The colour coding of O-rings for R134a refrigerant circuits has been discontinued. Coloured and black O-rings are used.

⇒ Rep. gr. 87

⇒ Parts catalogue

2.1.13 Pipes and hoses in refrigerant circuit

The mixture of refrigerant oil and refrigerant R134a attacks certain metals (e.g. copper) and alloys and dissolves certain hose mate‐ rials. Therefore, always use genuine replacement parts.

The hoses and pipes are held together with screwed joints or special push-fit joints.

Note

When assembling screwed joints, be careful to comply with the prescribed torques, and when working on push-fit joints, be care‐ ful to use the disconnection tools provided.

24 Rep. gr.00 - Technical data

Volkswagen Beetle 2012, Caddy 2004, Caddy 1997, Bora 1999, Caddy 2011 Workshop Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

1.1 Introduction

1.2 Additional information

1. General notes on air conditioning systems 1

1.3 Basics of air conditioning

1.3.1 Physical basics:

1.3.2 Heat always flows from warmer to colder material

1.3.3 Pressure and boiling point

1.4 Vapour pressure table for refrigerant R134a

1.5 Refrigerant R134a

1.5.1 Physical data of refrigerant R134a

1.5.2 Critical point

1.5.3 Environmental aspects of refrigerant R134a

1.6 Characteristics of refrigerant R134a

1.6.1 Trade names and designations

1.6.2 Colour

1.6.3 Vapour pressure

1.6.4 Physical properties of R134a

1.6.5 Effects on metal

1.6.7 Water content

1.6.8 Combustibility

1.6.9 Charge factor

1.6.10 Detecting leaks

1.7 Refrigerant machine oil

1.7.1 Properties of refrigerant oils

1.8 Comfort

1.8.1 Environmental aspects

1.9 How air conditioning works

1.10 General safety

1.10.1 Product characteristics

1.10.2 Handling refrigerants

1.10.3 Wear protective glasses

1.10.4 Wear protective gloves and apron

1.10.6 Do not breath in refrigerant vapour

1.10.7 Absolutely NO SMOKING

1.10.9 Pungent smell

1.10.10 First aid

1.10.11 Handling pressure tanks

1.10.12 Do not heat above 50°C

1.10.13 Do not apply uncontrolled heat

1.10.14 Seal empty containers

1.10.15 Safety instructions for using extraction and charging equipment

1.12 Basics for working on refrigerant circuit

1.12.1 O-ring

2.1 Refrigerant circuit components

2. General information on refrigerant circuit 17

2.1.2 Air conditioning system compressor with magnetic clutch:

2.1.3 Air conditioner compressor without magnetic clutch

2.1.5 Electrical air conditioner compressor for high-voltage system

2.1.6 Condenser

2.1.7 Evaporator

2.1.8 Reservoir

2.1.9 Restrictor

2.1.10 Receiver

2.1.11 Expansion valve

2.1.12 O-ring

2.1.13 Pipes and hoses in refrigerant circuit