The need for an authentic and reliable report relating to the repairs
and rehabilitation of a faulty air-conditioner is inevitable.
Many homes and offices uses the air-conditioner to cool he temperature
in their respective homes. So the maintenance of the air-conditioner
should be a top priority of every individual in order to avoid huge
expenditure in the repairs of the system. It’s for this reason that
this report is written for the benefit of those whom are privileged to
own an air-conditioner in their respective homes.
This report is based on ordinary and advanced level research, in order
to aid easy reading and understanding for an average person. This
report begins with an introduction into the relevance of an air –
conditioner, the history, description of the important components of the
air – conditioner, the general maintenance and regular maintenance an
serving, one is expected to carryout for effective performance of the
air-conditioner and the faults discovered together with the repairs
Subsequently, advanced information pertaining to the repairs and
calculations involving a faulty air conditioner have been giving certain
sections of this report, which will be beneficial to those interested
in the repairs of the faulty air conditioner.
TABLE OF CONTENTS
1.2 Literature Review
1.3 Definition Of An Air Conditioner
1.4 Why We Use Air Conditioner
1.5 Significance Of Study
1.6 Limitation Of Study
1.7 Basic Components Of Air Conditioner
1.8 Functions Of The Components
1.9 Air Conditioning System And Properties Of Air
2.1 Statement Of Problem/Faults
2.2 How To Detect The Faults
2.3 Brief Explanation Of Major Tools And Equipment’s Used
2.4 Detecting Of Faults
2.5 Correction Of Faults
2.6 Connection Of The Electrical Components
2.7 Detection Of Shortage Of Gas In The System
2.8 Replacement Of Front Grille And Filter
3.1 Maintenance Of Breakdown Air Conditioner
3.2 Causes Of Air Conditioner Breakdown
3.3 What Is Breakdown Maintenance
3.4 Categories Of Maintenance
3.5 Groups Of Air Conditioner Maintenance
3.6 General Maintenance And Repairs Schedules
3.7 Safety Precautions
4.1 Principle Of An Air Conditioner
4.2 Mathematical Representations And Thermal Efficiency
4.3 Mathematical Analysis And Calculations
5.1 Cost Analysis
the years, all the tropical countries have been faced with the problem
of air around them. The relative humidity of air in most of the tropics
is very low; Hence the comfort is not there with the populace
especially in the places of work. This consequently reduces the work
rate of workers thereby affecting the GROSS NATIONAL PRODUCT of a
To this effect, the engineers and scientists are looking into the
methods of bringing comfort to the people while at home and at work.
They produced an appliance to help produce a cooler temperature for
individuals known as AIR CONDITIONER. This appliance has been in
operation for a very long time but most users prefer dumping their old
ones for new Air conditioner due to lack of knowledge on how to
maintain, repair or even rehabilitate minor faults in an air
1.2 LITERATURE REVIEW
origin of an air conditioner is necessary to trace. Its original
conception, and the people that were involved in its production at its
An air conditioner was gradually
developed and produced for cooling, cleaning heating and facilitating
ventilating processes such as:
The end of the 15th century, Leonardo da rinci had built the first ventilating fan.
In the year 1959, Boyle and also in the year 1800, Dalton discovered both discovered laws for ideal gases.
In 1815 Robertson Buchanan published the first book on heating and ventilation.
In the middle of the 19th century fans, boilers and radiators had been invented.
Alexander Twinning started commercial production of water ice, using the
compression pump and sulphuric either as refrigerant.
Second half of 19th century, brought about the further development of ice making and air conditioning processes.
In the 20th
century, Willis H. Carrier who is known as the “Father of Air
Conditioning” designed and installed the first year round air
conditioning system. It was performing the four major functions of
heating, cooling, humidifying and dehumidifying of the air or rather
using the air washer.
H. Carrier (1976 – 1950) developed the applications of a forced draft
fans, pipe coil heaters, centrifugal compressors, invented a
psychometric chart and generally laid down the theory of air
conditioning on a complete thermodynamic basis. On the most famous
paper “Regional psychometric formulae” published in the year 1911,
Willis Carrier related the dry bulb, we bulb; dew point temperatures of
air with its sensible, latent and total heat and presented a theory
conditioning was increasingly been in use after Willis carrier’s
invention; in cotton, rayon, silk, paper, tobacco, cady pharmaceutical
and printing industries all around the world.
comfort for the people the air-conditioning was first installed in
cinema building in 1920 in Chicago, employing dry ice machine and in
1922 in Los – Angeles using ammonia compressors.
brought about an increase in demand and expansion in air conditioning
equipments sales to cinema, office building, hostels, hospitals, airport
terminal, departmental stores, banks, shops, and individual homes etc
in the market, the buyers were assumed of better packages than the
1.3 WHAT IS AN AIR CONDITIONER
provision of it can be defined as the process of treating air in order
to clean or purify it, to control its temperature and humidity by
heating or cooling and by humidifying and dehumidifying and to supply
sufficient outdoor air for ventilation. The word air conditioning is
employed to any process or system which fulfil all these requirements.
1.4 WHY WE USE AIR CONDITIONER
to science, oxygen is needed for human life and for any living thing to
stay alive, is one of the vital use of an air conditioner.
acts as a dilatants; ie the amount of air required depends on the
permissible contaminant level for the room. The contaminant may be C02 human skin or omission from any other processes.
3. The air condition promotes air movement in t he space; this brings one of the environment comfort factors.
4. An air conditioner controls air borne contamination i.e industrial ventilation.
1.5 SIGNIFICANCE OF STUDY
purpose of studying about Air – conditioner is to show how
necessary it is needed in a house. In other words, when one owns this
appliance and its not functioning properly due to a faulty in the
system, this study is very important and a guide to the relevant steps
of maintaining and knowing what one should do in order to discover a
fault in the air conditioner and having a solution.
1.7 BASIC COMPONENTS OF AN AIR CONDITIONER
The air conditioning system has four basic component parts. These are as follows:
3. Metering device
Furthermore, there are other components as follows:
1. Fan motor
2. Fan blade
3. Over load
5. Drier strainer
7. Flexible cable
8. Air conditioning junction box
10. Fiber (lagging) material
12. The working fluid (refrigerant)
13. Back cover (Hide)
17. Fan Blower
1.8 FUNCTIONS OF THE COMPONENTS
COMPRESSOR: The compressor can be explained as the heart of mechanical air conditioning system.
The compressor pumps the refrigerant gas throughout the entire system.
It draws cool refrigerant gas through the suction line from the gas
there by raising the pressure and temperature and then pumps it into the
There are various types of compressor namely:
1. Rotary compressor
2. Reciprocating compressor
3. Centrifugal compressor
4. Screw compressor.
THE CONDENSER: The
condenser is a component in the air conditioner, which transfers heat
from air conditioning system to a medium where they can be absorbed and
moves it to the final disposal point.
The condenser is the channel through which unwanted heat is liberated
out of the air conditioning system. It is the condenser that
superheated high pressured refrigerant vapour is cooled to its boiling
(conferring) point by rejecting sensible heat. The additional rejection
of latent heat causes the vapour to condense to the liquid state.
TYPES OF CONDENSER
1. Water cooled shell and cool condenser
2. Water cooled shell and tube condenser
3. Air cooled condenser
4. Evaporative condenser.
The evaporator is a device in the low pressure side of an air
conditioning system through which an unwanted heat flows. The
evaporator absorbs the heat into system in order that it may be moved or
transferred to the condenser. The evaporator is also known as a
“cooling” blower cool, “Chilling unit “.
Its ultimate function is to absorb heat from the surrounding air or
liquid and by means of refrigerant the heat is carried along out of the
TYEPS OF EVAPORATOR
1. Shell and tube direct expansion evaporator
2. Shell and tube flooded evaporator
3. Submerged coil evaporator
4. Boud lot/coolers.
OTHER COMPONENTS AND THEIR FUNCTIONS
DRIER/STRAINER: This serves as the filter for the filtration of the refrigerant gas, also small amount of heat reduction takes place in it.
OVER LOAD AND RELAY: These
are sensitive materials inside the air conditioner, they serve the
purpose of protecting the compressor by tripping off any unwanted
current coming into the compressor thereby preventing damage to
can be explained as when the air conditioner attains its maximum
cooling point, the thermostat will cut off current; also, it trips off
the compressor when the voltage is low.
FLEXIBLE CABLES: Flexible cables are their copper wire that supplies current from the power source with the help of plug to the air conditioner.
BULB: Bulb is a power indicator, it lights up when the current has entered the air conditioning system.
FOAM THAT COVERS THE INTERNAL BODY: This
is a substance which covers the in cover of the air conditioner so as
to avoid loss of cool air or escape of cooled air that comes from the
switch controls the current coming into the air conditioning system;
that is, it is the key which opens and closes (on and off) the
activities of the air conditioner.
FRONT GRILLE: Front grille is used to cover the front part of an air conditioner in other to prevent damages to other components a round it.
FAN MOTORS: It
is known as the unit in between the fan blade and the fan blower where
the current is produced to drive the fan blade and fan blower.
FAN BLADE: The fan blade is located at the back of the condenser. It blows away hot air from the room.
FAN BLOWER: This can be located at the back of the evaporator system. It blows cool air from the system into the room.
FILTERS: This is an instrument that filters the air in other to prevent the dust in the air from entering the evaporator.
capacitor is a unit used to charge and draw more current; it is also
used for starting period in maintaining the lowest mark of change in
temperature from hot to cold.
CAPILLARY TUBE/METERING DEVICE: This
device is carefully calibrated in length and inside diameter to meet
the exact amount of liquid refrigerant flow required for each unit.
FIBER (LAGGING) MATERIAL: This
material is mostly made of wool and it is used to prevent the loss of
heat in order to maintain the temperature of the air conditioner.
1.9 AIR CONDITIONING SYSTEM/THE PROPERTIES OF AIR
is the medium at which an air conditioner works, before we cool or heat
it, we have to condition it first; by so doing, it cools or heats a
building and makes it s occupants comfortable.
An air conditioning is the complete conditioning of air by heating,
cooling, humidifying, dehumidifying, filtering, cleaning and
All the systems do not require the induction of all these
conditioning processes, but each system requires consideration of all
the processes. The atmospheric air is composed of (i) Dry air (ii)
Moisture in the form of water vapour or s team (iii) impurities such as
smoke, dust and toxic gases.
Pure dry air is a moisture of several gases like oxygen, nitrogen and
varying amount of carbon (iv) oxide and the inert gases.
PERCENTAGE BY WEIGHT OF AIR
PERCENTAGE IN DRY AIR