How to Install a Ductless Mini-Split Air Conditioner

ductless AC installation

When it comes to installing something in your home yourself, it’s vital to do it the proper way – not only for the safety of your family, but also to get the maximum value from your product.

If you’re attempting to install a ductless mini split AC system on your own, first off we’d like to say hat’s off to you! It’s no easy task.

Should you choose to move forward, here are a few important steps to follow:

  • First and foremost, ALWAYS shut off the electricity to the circuit.
  • Make certain the mounting bracket is level.
  • Mark the spot for the electrical cable, refrigeration lines and the condensate discharge line.
  • From the inside, drill a hole with a three inch diameter masonry coring bit and a rotary hammer. Finish drilling the hole from the outside after the bit punctures the wall.
  • Finish placing level mounting bracket on the wall.
  • Install the air conditioning system on the bracket.
  • Pass the condensate and refrigeration lines through the wall.
  • Below the hole in the exterior wall, attach a vertical chase. This is where all the lines and cable will be housed.
  • Attach a PVC pipe to the condensate discharge line.
  • Use duct tape to attach the discharge line to the pipe.
  • Screw on a metal “C” clamp to the lower portion of the pipe.
  • Remove compression fittings from the ends of the copper lines and then carefully bend the copper refrigeration lines into the chase.
  • Slide a brass nut onto the copper tubing and flare the end.
  • Take the flared end of the tube and hold it against the end of the refrigeration line. Hand tighten the nut.
  • Place the condensing unit (located outside) on a level pad adjacent to the chase.
  • Tighten the compression fittings on the refrigerant lines and wrap piping insulation around each line.
  • Run a conduit from an outdoor electrical box to the condenser unit and feed the wires through the conduit.
  • Take nonmetallic electrical cable from the condenser unit and run it through the hole in the wall to the indoor unit.
  • Place a cover on the chase to protect the lines and cable.
  • Pressure test the system with nitrogen to 300 pounds per square inch.
  • Vacuum out the nitrogen and then release the refrigerant into the system by opening the valves.
  • Turn on the electricity.

Time to test the system!

More of a visual learner? Check out this video supplied by This Old House plumbing expert Richard Trethewey:

If you live in the metro Atlanta area and want to guarantee proper installation and not have to hassle with it on your own, contact an HVAC professional at Gagne Heating and AC.