Mazda CT-L1005 Training Manual

Training Manual

Basic Climate Control

CT-L1005

No part of this hardcopy may be reproduced in any form without prior permission of
Mazda Motor Europe GmbH.

The illustrations, technical information, data and descriptive text in this issue, to the best of our
knowledge, were correct at the time of going to print.

No liability can be accepted for any inaccuracies or omissions in this publication, although every
possible care has been taken to make it as complete and accurate as possible.

© 2005

Mazda Motor Europe GmbH
Technical Services

Basic Climate Control Table of Contents

Introduction .......................................................................................01-1

Fundamentals....................................................................................02-1

Physical Comfort....................................................................................... 02-1

Getting Comfortable............................................................................ 02-2

Changing the Air Temperature ........................................................... 02-2

Warming the Air in the Vehicle ........................................................... 02-4

Cooling the Air in the Vehicle.............................................................. 02-5

Latent Heat......................................................................................... 02-6

Dehumidifying the Air.......................................................................... 02-8

Filtering the Air ................................................................................... 02-9

Refrigerant.............................................................................................. 02-10

Pressure-Temperature Relationship of R134a ................................. 02-10

Refrigerant in a Closed Container..................................................... 02-11

Handling Refrigerant......................................................................... 02-12

Environmental Impact.......................................................................02-12

Compressor Oil.......................................................................................02-13

Moisture in the A/C System..................................................................... 02-13

A/C System ........................................................................................03-1

System Overview......................................................................................03-1

A/C System with Expansion Valve...........................................................03-3

Parts Location...........................................................................................03-3

Compressor .............................................................................................. 03-4

Vane Rotary Compressor................................................................... 03-5

Scroll Compressor.............................................................................. 03-6

Swash Plate Compressor................................................................... 03-7

Condenser ................................................................................................ 03-8

Fin and Tube Condenser....................................................................03-9

Multiflow Condenser......................................................................... 03-10

Multiflow Condenser with Sub-cooler................................................ 03-11

Receiver / Drier.......................................................................................03-12

Expansion Valve..................................................................................... 03-14

Evaporator .............................................................................................. 03-16

Refrigerant Lines..................................................................................... 03-19

Control .................................................................................................... 03-20

Refrigerant Pressure Switch............................................................. 03-20

Low / High Pressure Switch.............................................................. 03-20

Medium Pressure Switch..................................................................03-21

Magnetic Clutch................................................................................ 03-21

Wiring Diagram................................................................................. 03-22

Curriculum Training

Table of Contents Basic Climate Control

A/C System with Fixed Orifice.......................................................................... 03-23

Parts Location.........................................................................................03-23

Compressors........................................................................................... 02-24

Variable Displacement Swash Plate Compressor ............................ 03-24

Variable Displacement Scroll Compressor ....................................... 03-25

Fixed Orifice ..................................................................................... 03-25

Accumulator / Drier........................................................................... 03-27

Control .................................................................................................... 03-28

A/C Cycling Switch ........................................................................... 03-28

Refrigerant Pressure Switch............................................................. 03-29

Wiring Diagram................................................................................. 03-30

Component Overview ............................................................................. 03-31

Heating System .................................................................................04-1

System Overview......................................................................................04-1

Thermostat................................................................................................ 04-2

Heater Core .............................................................................................. 04-2

Water Pump..............................................................................................04-2

Radiator .................................................................................................... 04-2

Diagnosis and Repair........................................................................05-1

Pressure Gauges......................................................................................05-1

Refrigerant Pressure Check ............................................................... 05-2

Leak Testing ............................................................................................. 05-4

Control System Check .............................................................................. 05-5

A/C Service Machine ................................................................................ 05-5

Draining the A/C System .................................................................... 05-6

Evacuating the A/C System................................................................ 05-6

Filling the A/C System ........................................................................ 05-6

Summary of Refrigerant Draining and Filling Procedures................... 05-7

Component Replacement ......................................................................... 05-8

Compressor Damage................................................................................ 05-9

Odours from the A/C System.................................................................... 05-9

Diagnosis on the Heating System...........................................................05-10

Thermostat ....................................................................................... 05-10

Heater Core...................................................................................... 05-10

Curriculum Training

Basic Climate Control Introduction

Introduction

• A/C (Air Conditioning) has been available for automobiles since the 1930’s. Here in
Europe in the last five years there has been a large increase in the number of vehicles
equipped with A/C. This course does not just cover air conditioning, but also the heating
system, hence the name Basic Climate Control. The climate control system in a vehicle
does not only ensure the comfort of the passengers, there is also a safety aspect.
Without a properly functioning climate control system, it might not be possible to keep
the windscreen free from misting up during damp or cool weather.

• Mazda uses two different A/C systems on its vehicles; a system using an expansion
valve, and a system using a fixed orifice. The components and operation of both systems
will be covered.

• The majority of Mazda vehicles currently sold in Europe are equipped with an A/C
system. On some models A/C is standard.

• Diagnosing and repairing climate control system related concerns requires working with
a refrigerant under pressure. Improper handling of the refrigerant could lead to serious
injuries. Follow the safety guidelines both here in this training manual, and in the service
literature. This course is a theoretical and practical guide to gain general and Mazda
specific knowledge about the different climate control systems, including their
components, function, and diagnosis.

• Anyone associated with the diagnosis and repair of climate control systems must have
the knowledge to deliver a “Fix it right first time” repair. Therefore, the Mazda Masters
development and qualification path provides the following training courses required for
servicing and diagnosing climate control systems:

– Basic Climate Control CT-L1005
– Advanced Climate Control CT-L2009

• The ranking of this course within the Mazda Masters educational system is Level 1 –
‘Mazda Technician’. It is intended for technicians who already have experience in
maintaining and repairing Mazda vehicles and have previously attended the course
“New-To-Mazda” CT-L1001.

Curriculum Training 01-1

Introduction Basic Climate Control

• The training manual “Basic Climate Control” is divided into the following main chapters:

– Fundamentals
– A/C System
– Heating System
– Diagnosis and Repair

NOTE: The data, tables, and procedures presented in this training manual serve only as

examples. They are taken from the service literature and subjected to major or minor
changes over the course of time. To prevent any mis-diagnosis, always refer to the
current service literature while working on climate control systems.

01-2 Curriculum Training

Basic Climate Control Fundamentals

Fundamentals

Physical Comfort

• When do we feel comfortable? What is comfort? When we aren’t comfortable, how can
we become comfortable?

• There is a norm that shows where most people find it comfortable based on the air
temperature, and relative humidity. There are also other factors not shown on this graph
that affect our comfort, such as how clean the air is and if there is an unpleasant
draught, or perhaps a pleasant breeze.

L1005_044

X Temperature Y Relative humidity
1 This area represents 90% of all outside

conditions

2 This area shows the ‘comfort zone’

Curriculum Training 02-1

Fundamentals Basic Climate Control

Getting Comfortable

• To change the level of comfort in a building there are several possibilities: open a
window, turn on a fan, adjust the thermostat, take some clothes off, or put some clothes
on. While it’s possible to do all of these things in a vehicle, there are of course practical
limitations. When driving in the rain, opening a window becomes impractical. The driver
of the vehicle might also find it difficult to keeping taking clothes off, and putting clothes
on.

• So a vehicle has a climate control system to allow the driver to create a comfortable
climate. To allow the driver to do this it has to be possible to change the two main factors
that affect our comfort: temperature and humidity. At the same time the air needs to be
cleaned, and the direction and speed of the air stream must be controllable.

Changing the Air Temperature

• The air entering the vehicle can be warmed, or the warmth can be taken from it. There is
no way to create ‘cold’. It is important to keep in mind that heat always travels from

warm to cold. The two following examples illustrate this fact.

02-2 Curriculum Training

Basic Climate Control Fundamentals

• In the first example a cold glass of water is brought into a warm room. The water will
absorb some of the heat from the air in the room, and settle to the ambient temperature
of the room. The heat travels from the warmer surroundings to the cooler water.

L1005_001

• In the second example a hot cup of coffee is brought into a warm room. The coffee gives
off the heat to the air in the room, and will settle to the ambient temperature of the room.
The heat travels from the hot coffee to the cooler surrounding air.

L1005_002

Curriculum Training 02-3

Fundamentals Basic Climate Control

Warming the Air in the Vehicle

• To carry the second example across to the vehicle, think of the heater core as the cup of
coffee being brought into a relatively colder room. The heater core gives its heat up to
the outside air that comes in contact with the fins. The heat travels from the warm heater
core to the cold air. Unlike the coffee in our example, the heater core receives a
continuous flow of hot coolant from the engine, and so will continue to give off heat as
long as the engine is running.

1 Cold air 3 Heater core
2 Warm air

L1005_004

02-4 Curriculum Training

Basic Climate Control Fundamentals

Cooling the Air in the Vehicle

• The example of the cold glass of water can be partially compared to the evaporator. The
evaporator is filled with a cold liquid, and this liquid absorbs the heat from the air as it
comes in contact with the fins of the evaporator. The heat travels from the hot air to the
cold evaporator.

L1005_003

1 Warm air 3 Evaporator
2 Cold air

• This heat absorption process in the evaporator is a little more complicated than the
heating process in the heater core. As the refrigerant passes through the evaporator, it is
a low pressure, cold liquid. As the warm air comes in contact with the fins of the
evaporator, the heat from the warm air is conducted through the metal fins and warms
the refrigerant flowing through the internal passageways. This warmth causes the
refrigerant to boil. During this boiling process the heat energy from the hot air entering
the vehicle is transferred to the refrigerant.

• As the refrigerant leaves the evaporator is will be a low-pressure gas. The heat energy
absorbed was used to change its state from a liquid to a gas (to boil it). The end effect
for the air is that as it comes out the other side of the evaporator it is now colder. The
two physical principles that allow this are the latent heat of vaporization, and the

pressure-temperature relationship properties of the refrigerant.

Curriculum Training 02-5

Fundamentals Basic Climate Control

Latent Heat

• The following graph shows the amount of heat added to 1 kg of water on the horizontal
axis, and on the vertical axis shows the temperature of the water. In the first stage the
water is frozen, and as heat is added to it, the temperature rises. As soon as the ice
reaches 0 °C it starts to melt. At this point all the heat energy is used to change the ice to
water; this is called the latent heat of fusion.

• Stage 2 shows that even though the entire energy (334 kJ) is added to the ice/water
mixture, the temperature does not change. Only when all of the ice is melted, does the
temperature start to rise again in direct relation to the amount of heat added (stage 3).
This is because the energy added is no longer required to change the ice to water, and
now the energy being added increases the temperature.

• At 100 °C the water starts to boil. At this point the temperature stops increasing, since all
the energy is needed to change the state from a liquid to a gas. This is known as the
latent heat of vaporization. This physical property is critical to the functioning of the
A/C. Stage 4 shows that the entire energy (2,258 kJ) is absorbed without increasing the
temperature of the water/steam mixture. This is the physical property that allows so
much heat to be taken from the warm air entering the vehicle.

02-6 Curriculum Training

Basic Climate Control Fundamentals

X Heat energy Y Temperature
1 Ice being warmed 5 Steam being warmed
2 Ice changing to water 6 Latent heat of fusion
3 Water being warmed 7 Latent heat of vaporization
4 Water changing to steam

L1005_022

Curriculum Training 02-7

Fundamentals Basic Climate Control

Dehumidifying the Air

• The air entering the vehicle normally has a relatively high humidity. When this humid air
comes in contact with the cool surface of the evaporator the moisture in the air will
condense as tiny droplets of water. These water drops will accumulate and run down the
evaporator, and leave the vehicle through the drain tube.

• There is no way to actively control how much moisture will be taken from the air, this is
determined by the dew point, which depends on the current air temperature and the
relative humidity of the air. Operating the A/C allows the evaporator to cool down, and for
the moisture in the incoming air to condense. This process can also be performed when
heating or defrosting, by turning the A/C on, and then selecting a warmer temperature.
This is especially effective when demisting or defrosting.

NOTE: This is the only one of the comfort factors that cannot be directly influenced by the

driver. The relative humidity can be indirectly reduced by operating the A/C and
forcing the humid air through the evaporator.

02-8 Curriculum Training

Basic Climate Control Fundamentals

Filtering the Air

• A mostly forgotten aspect of our feeling of comfort is how clean the air is. When the air is
clean it feels comfortable even at warmer or colder temperatures than normal. Add to
that the number of people today suffering from allergies (such as a pollen allergy etc.),
and the benefit of a filter can quickly be seen.

• The filter in the HVAC (Heating, Ventilation, Air Conditioning) system filters both the
fresh air and the recirculated air. A certain amount of smaller particles that pass the filter
are also trapped in the condensed water, which accumulates on the evaporator.

NOTE: The cabin filters used in Mazda vehicles cannot be cleaned and must therefore be

replaced at certain intervals (see the workshop manual). But if a customer drives in
dusty areas, or often drives in heavy stop and go traffic, a more frequent change
interval might be required.

L1005_009

1 Unfiltered air 3 Filtered air
2 Air filter

Curriculum Training 02-9

Fundamentals Basic Climate Control

Refrigerant

• The refrigerant used in current Mazda vehicles is called R134a. It is a hydrofluorocarbon
(C
with the fact that it does not harm the ozone layer, makes it an almost perfect substance
for A/C. However, R134a does still contribute to the greenhouse effect.

NOTE: Older Mazda vehicles use R12 refrigerant, which must not be used anymore. In

Pressure-Temperature Relationship of R134a

• This chart shows the relationship between pressure and temperature for the refrigerant.
At normal atmospheric pressure of 1 bar, refrigerant will boil at –26°C. Above this curve
(area 1 in the diagram) the refrigerant is gaseous, below the curve (area 2 in the
diagram) it is liquid.

) that at normal atmospheric pressure boils at –26°C. This property, combined

2H2F4

addition, R12 and R134a must not be mixed.

L1005_023

X Pressure Y Temperature
1 Gaseous refrigerant (above the curve) 2 Liquid refrigerant (below the curve)

02-10 Curriculum Training

Basic Climate Control Fundamentals

Refrigerant in a Closed Container

• When R134a is in a closed container, and the container is in a surrounding with an
ambient temperature above –26°C, some of the liquid will boil off until pressure is
developed. The pressure will be equal throughout the entire container, and the
developed pressure will keep a portion of the refrigerant liquid. As the container heats
up, the liquid refrigerant will expand in volume. If the container is allowed to warm up to
the point where the liquid has expanded to fill the entire volume of the container, the
pressure will then increase rapidly, and the container could rupture.

CAUTION: Filling a container more than 60%, and storing a container near sources of heat

or in direct sunlight can cause serious injury.

1 Properly filled container 4 Ruptured container
2 Overfilled / overheated container 5 Liquid refrigerant
3 Dangerously overfilled / 6 Gaseous refrigerant

overheated container

• In the event of a rupture, the resulting explosion is much more violent than say a
comparable rupture with compressed air. The refrigerant leaving the container will be
nearly instantaneously vaporized, causing a rapid increase in the volume of the
refrigerant. For this reason the containers are delivered with a liquid fill volume of no
more than 60% (at 20° C).

L1005_041

Curriculum Training 02-11

Fundamentals Basic Climate Control

Handling Refrigerant

• Because R134a boils at –26°C, if a line is opened while there is refrigerant still in the
system, the refrigerant will boil by absorbing heat from the surrounding area. This means
that if your hand comes in contact with the refrigerant as it escapes, you will experience
acute frostbite (a strong burning sensation). To avoid this, insulated rubber gloves
should be worn. Normal cloth or leather gloves provide little protection, as the heat will
be absorbed through the material.

• Protective safety glasses should be worn to protect against dirt being blown into the eyes
in the event that a high-pressure line is opened.

• The A/C service equipment should be used in accordance with the manufacturers
instructions.

• Keep in mind that R134a is heavier than air and will sink to the ground, that means that
working in a pit or other low lying area while servicing the A/C is not recommended,
because large amounts of released refrigerant could displace the air, and cause
suffocation.

• While R134a is not flammable, it could develop into a toxic compound (hydrogen
fluoride) when it comes in contact with an open flame, electrical arcing, or a source of
extreme heat

Environmental Impact

• R134a is an improvement on its predecessor R12, but it still is harmful to the
environment. R134a does not contribute to depletion of the ozone layer like R12 did, but
it still contributes to the greenhouse effect. When one gram of R134a is released to the
atmosphere, it has the same effect as 1.2 kg of CO
For reference, 1 g of R12 has the same effect as 8.5 kg of CO
atmosphere.

• It should also be kept in mind that any R134a that is released into the atmosphere will,
on average, not break down for 14 years. While this is better than the 100 years it takes
R12 to break down, it is still not desirable.

being released to the atmosphere.

2

being released to the

2

02-12 Curriculum Training

Basic Climate Control Fundamentals

Compressor Oil

• The compressor oil in the A/C circuit is required to lubricate the moving parts of the
compressor. The oil is carried throughout the system by the refrigerant. The compressor
oil is highly hygroscopic PAG (Poly-Alkaline Glycol), meaning it easily absorbs moisture
(much like brake fluid does).

NOTE: Older Mazda vehicles with R12 refrigerant use mineral compressor oil, which must

not be used anymore. In addition, mineral oil and PAG oil must not be mixed.

• The current range of Mazda vehicles all use PAG oils, but there are several different
types available. They can have differing characteristics such as different viscosity. For
this reason, the different compressor oils are not interchangeable. This means that when
servicing a vehicle, the correct oil needs to be put into the A/C system.

NOTE: Compressor oil needs to be properly disposed of just like any other environmentally

harmful fluids (brake fluid, engine coolant, etc.). Consult the local authorities to find
out if there are special requirements for discarding the oil in your country.

Moisture in the A/C System

• Water in the closed A/C system is an undesired substance, because it causes corrosion
on the system components. The only way that water should be able to enter the system
is being transported as moisture in the air. When a system still has refrigerant in it, there
is pressure, and there is no way for moisture to enter the system. When a system is
opened, and the refrigerant is removed (during service), or the system is open to the
atmosphere (as a result of an accident), then it is possible that air enters the system. In
the air is moisture, and this moisture can be trapped in the system.

Curriculum Training 02-13

Fundamentals Basic Climate Control

Notes:

02-14 Curriculum Training