Contractor Help

• Unlike a window air conditioner, a mini split does not plug into a standard electrical wall socket. Most require separate electrical circuits for indoor and outdoor locations. The outdoor unit requires a 240 volt circuit for the compressor. The indoor unit requires a 120 volt circuit for the fan and indoor controls. If you are not comfortable working with electricity, hire a licensed electrician to do the wiring.
  
  

Size and Location

• Geographic location and room size will determine the required size and capacity of the mini split air conditioner. Warmer climates require more cooling capacity than cooler climates. Larger rooms, rooms with many windows and rooms with a lot of sunlight require more cooling capacity than smaller, closed off rooms.
  
  An undersized system will struggle to keep up in hot, humid weather and will shorten its lifespan. An over sized unit will "short cycle," meaning the system will turn off and on in short intervals. The mini split manual specific to your model will contain the installation requirement information.
  
  An over sized air conditioner will cool the room too quickly and satisfy the thermostat before all the air in the room has had a chance to go through the cooling and dehumidifying process. When the system shuts off, the air temperature will quickly rise and the air conditioner will turn on again, repeating the process and never reaching a comfortable room temperature and humidity level.
  
  

Refrigerant Line Set

• A mini split refrigeration line set consists of two copper tubes, one slightly larger than the other, that tie the indoor and outdoor units together. The line set completes the circuit from the indoor evaporator coil to the outdoor condensing coil and is made of soft, flexible tubing so it is easy to maneuver and bend into position. This flexibility also makes the refrigerant line set easy to kink. Any kinks must be cut out and replaced with a new section of copper tubing.
  
  Always try to locate the outdoor unit as close to the indoor unit as possible. Also try and run the line set in one piece. Cutting the line set and brazing in elbows and other copper fittings increases the chances of future leaks and problems.
  
  

Drainage

• Drainage is key. All the humidity the mini split air conditioner takes out of the air is funneled to a pan in the bottom of the indoor unit. A hose connects to the pan and exits the same hole as the refrigerant line set. Generally, the hose is brought straight down the side of the house where the water is drained off into the yard.
  
  The most critical part of installing a mini split air conditioner is hanging the indoor unit and making sure the refrigerant line set and the drain tube or pipe are not damaged. The pitch of the drain line is critical because the system drains by gravity. Once the indoor unit is connected and hanging on the wall, the drain line is hidden, so care must be taken during the installation to ensure a clean, proper fit and an angle for the drain line.