CHAPTER ONE
1.1     INTRODUCTION
All most all the countries in the tropical are faced with one problem of air or the other.  Ranging from not being contented with the moisture, the relative humidity of the air and its cleanliness.
These air problems can cause a lot of discomfort especially in the places of work, which consequently reduces the working efficiency of an individual.
Thee problems of air led the engineers and scientist to look into methods of bringing comfort to people, which gave birth to the invention of air condition.  Air condition suck in air in the room and purify it, and then heat and cool and supply them back to the room by the process of heating, cooling, humidifying, dehumidifying, filtering, cleaning, distribution through the help of a blower in the air condition.
It has been in operation for a long time but most users prefer new modern air conditioner due to the modern technology introduced in it. Today pure air purification can be made possibly by the use of air conditioner.
1.2     HISTORY OF REFRIGERATING MACHINE
Air conditioning can about as a result of water soaked mat that were hung across window and doors to produce cooling system by evaporation during hot dry weather.
WILLIAM THOMPSOM, who later became LORD KELVIN, contributed immensely to the development of refrigeration, some of his other works included the absolute temperature scale, the law of conservation of energy etc.  However, it w as WILLIS CARRIER who conducted the research which when published in 1911, gave the foundation on which to days air conditioner was built.
In the early stage of its invention, air conditioner was a hazard because of the explosive or poisonous nature of the refrigerants in use then.  It was in 1928 that suitable refrigerants were discovered and used for more effective air conditioning.  This led to a high increase in demand and expansion in air conditioning equipments.
1.3     SIGNIFICANCE OF STUDY
This study show how important an air conditioning unit is at home.  The study proffer a concise guide to relevant steps of maintenance, what to do in order to discover a fault in the air conditioner and how to remedy the situation.
1.4     LIMITATION OF STUDY
We are expected to explore all avenues and ways to find the sample and proper procedure in repairing the air condition given to us as our study, without any exception or delineated areas left out.  Basic maintenance of all types should be the bases of this study.