Indoor Concealed Units:

The indoor unit is installed inside the room to be air conditioned. It can be mounted on the ceiling, wall or simply as a console unit on the floor. The other term used for indoor unit is Fan Coil Unit (FCU). It consists of the following parts:

  • Evaporator Coil: the heat exchange is done with the room. It consists of fins and tubes.
  • Control Panel: user control the functions of the air conditioner. Displays at the panel may indicate the mode of operation, timer on/off status, fan speed and other special functions. Most newer units have remote control feature built into the system.
  • Air Filter: located in front of the evaporator coil to trap any dust or particles before going into the evaporator. This is usually washable and re-usable. Users are advised to clean it at least once in 3 months or more regularly if the environment is dirty.
  • Supply and Return Air Grills: where the air enters and discharge from the indoor unit.
  • Fan Blower: together with its motor used to control the fan speed of the unit. High, Medium, Low and Ultra Low speeds are usually designed for user’s selection.
  • Capillary Tube: used as an expansion device where the flow of the refrigerant depends on the tube internal diameter, shape and its length. This tube is usually used in smaller units. Larger Units use thermostatic expansion valve which has a controlling valve to control in greater precision the flow of the refrigerant.

Outdoor Concealed Units:

The outdoor unit is installed outside the building and consists of the fowling parts:

  • Compressor: the main component of the system and used to compress the refrigerant.
  • Condenser Coil: used to reject heat from the refrigerant to the outside air.
  • Condenser Fan: used in air-cooled condenser to help move the air molecules over the surface of the condensing coil, hence rejecting the heat from the indoor to the space outside the building.
  • Condenser Motor: the motor usually has two to three speeds. Smaller units may have only one speed of control and turns on/off simultaneously with the compressor.