How to Install a Ductless Air Conditioner
In this article, we will discuss the basics of installing a single-zone ductless air conditioner, also known as a mini split. These systems have been popular globally for over four decades and are gaining traction in North America due to their efficiency, functionality, and flexible installation options. Many ductless air conditioners sold in North America are single-zone systems.
Equipment Types
There are two main types of ductless air conditioners:
- Single-Zone: A “one-to-one” system with one outdoor unit and one indoor unit, designed to heat or cool a single space.
- Multi-Zone: A system with one outdoor unit connected to multiple indoor units, capable of heating or cooling multiple spaces separately.
What Size System Do I Need?
Before installation, perform a load calculation to determine the appropriate system size. This calculation considers factors such as windows, insulation, and house orientation to ensure optimal heating and cooling performance. An undersized unit won’t effectively heat or cool the space, while an oversized unit can cause mold issues and inefficient operation.
For this installation, a 12k ductless air conditioner with a white wall-mounted indoor unit has been selected. Additionally, verify that the home has sufficient electrical capacity for the new system. Consult a licensed electrician if modifications are needed.
Choosing the Right Brand and Style
Professional installers typically recommend major brands due to their superior after-sales support and extended warranties. Ductless air conditioners come in various styles, including ducted and ductless models. Most outdoor units are off-white, while wall-mounted indoor units are available in multiple colors and designs.
Placement of the Outdoor and Indoor Units
While mini split outdoor units operate quietly, they still produce some noise. Place the outdoor unit away from windows to minimize disturbances. Always refer to the manufacturer’s manual for proper clearances and installation guidelines.
Proper indoor unit placement is crucial for efficient heating and cooling. If the space is long and narrow, avoid placing the unit on the long wall, as this can cause air recirculation issues. Instead, install it on the short wall to distribute air evenly. Exterior walls are preferable for easier copper piping installation and proper condensation drainage. If an interior wall must be used, a condensate pump may be required.
Installation Process
With the equipment selected and placement determined, it's time for installation. Before proceeding, ensure that the electrical supply is ready and that an HVAC disconnect is available to power the system. In this installation, the outdoor unit is placed outside, just below the indoor unit inside.
Mounting the Indoor Unit
- Open the box and lay the unit face down on a padded surface.
- Remove the mounting plate from the back and secure it to the wall using appropriate hardware.
- Mark and drill a 2 ¾” hole at a slight downward angle for piping, wiring, and drainage. Install a wall sleeve for a clean look and proper sealing.
- Run the 14/4 power and control wiring into the back of the unit and connect it to the terminals.
- Carefully bend the piping to a 90° angle and secure it along with the drain line and wiring.
- Pass the piping, wiring, and drain line through the hole, then mount the indoor unit onto the wall plate.
Mounting the Outdoor Unit
- Use a wall bracket to keep the unit elevated above potential damage from pets, weeds, or lawn equipment.
- Secure the unit, ensuring manufacturer-recommended clearances are maintained.
- Avoid overtightening rubber vibration isolators to minimize noise transmission indoors.
Installing the Line Set Cover
- Install the Slimduct SD W lineset cover to protect the piping and wiring.
- Secure the base of the wall inlet at the hole and add straight ducts and elbows as needed.
- Ensure ample space for the piping, wiring, and drain hose.
Connecting the Piping
- Release the nitrogen pressure from the indoor unit and remove factory flare nuts.
- Cut and deburr the copper tubing, then make flares using a flaring tool.
- Apply refrigerant oil to the flare faces before connecting the pipes.
- Securely tighten all connections to manufacturer torque specifications.
- Route the copper piping along the Slimductbase to the outdoor unit and connect the wiring to the outdoor unit terminals.
Sealing and Final Steps
- Seal the penetration where the piping exits the wall using AP 100 putty to prevent pests, water, and air leaks.
- Snap the Slimduct covers in place and secure them with the provided stainless-steel screws.
- Install a bug stopper at the end of the drain hose and follow the manufacturer’s guidelines for refrigerant charging if required.
Note: This guide is for informational purposes only and intended as a reference for trained, licensed HVAC contractors. Always follow industry best practices and comply with local codes and regulations to ensure safety and proper installation.
