Mini-Split System Components & Functions

A mini-split system consists of two main units:

1. Indoor Unit (Evaporator)

2. Outdoor Unit (Condenser)
   These are connected by refrigerant lines, and the system operates without ductwork (ductless).

🔹 1. Indoor Unit (Air Handler / Evaporator)

Function:

• Pulls in warm air from the room

• Passes it over a cold evaporator coil filled with refrigerant

• Blows cooled air back into the room

Key Parts:

• Evaporator Coil – Absorbs heat from indoor air

• Blower Fan – Circulates air across the coil and back into the room

• Air Filter – Captures dust and debris from indoor air

• Thermistor / Temperature Sensor – Monitors room temperature to control operation

🔹 2. Outdoor Unit (Condenser)

Function:

• Receives warm refrigerant from indoor unit

• Releases heat absorbed from inside the home

• Sends cooled refrigerant back indoors

Key Parts:

• Compressor – The heart of the system; pressurizes refrigerant to circulate it

• Condenser Coil – Releases heat to the outside air

• Outdoor Fan – Blows air over the coil to help release heat

• Control Board – Coordinates communication between indoor and outdoor units

🔹 3. Refrigerant Lines (Line Set)

Function:

• Carry refrigerant between indoor and outdoor units

Two Copper Lines:

• Suction Line (larger, cooler) – Carries low-pressure refrigerant to the compressor

• Liquid Line (smaller, warmer) – Carries high-pressure refrigerant to the indoor coil

🔹 4. Drain Line (Condensate Line)

Function:

• Removes moisture condensed on the evaporator coil (dehumidification)

• Routes it safely outside or to a drain

🔹 5. Electrical Wiring / Communication Cable

Function:

• Powers the indoor unit (from the outdoor unit)

• Allows digital communication between the units for synchronized operation

🌀 How It All Works (Cooling Cycle):

1. Warm air from the room is drawn into the indoor unit

2. Air passes over the cold evaporator coil → heat is absorbed by refrigerant

3. Cooled air is blown back into the room

4. Warm refrigerant flows to the outdoor unit

5. Compressor pressurizes the refrigerant

6. Heat is released through the condenser coil outdoors

7. Cooled refrigerant returns indoors to repeat the cycle

🔄 In Heating Mode (via Reversing Valve):

• The indoor and outdoor coils swap roles

• Heat is pulled from outside and transferred indoors