Jeff Flowers on February 25, 2015 13 Comments A mini-split system is an excellent heating and cooling solution for small areas in the home where running ductwork is not a practical solution. Whether the home has a non-ducted heating and cooling system or there are renovations where additional rooms or living space is being added, a mini-split system is efficient and small enough to be used as the sole heating and cooling source for those areas. Consider Hiring a Professional While a mini-split system is easier to install because it has no ductwork, some installation steps may be a bit confusing and complicated for non-professionals to handle on their own. Not only does one need certain tools and knowledge to successfully install a mini-split system, but installation requires dealing with electrical and refrigerant components that may be locally and federally regulated in your state. Professional installation is highly recommended since the efficiency of your mini-split system depends on how well it is installed. To prevent problems with installation and operation, the indoor unit must be properly sized to accommodate the space it is being used for. Charging the refrigerant lines can be problematic for a nonprofessional who is attempting to install a mini-split system. Improper installation can cause the unit to short circuit, malfunction, and create a fire hazard to your home. It is best to hire a professional to save time, money, and to get it installed the right way from the start. However, while we recommend hiring a professional, if you want to give it a shot on your own, here are some general tips that will help you install your mini-split. Be sure to refer to the user manual that comes with your unit for more specific instructions Tools You Will Need: two open type or adapter torque wrenches vacuum pump with lines and adapters vacuum gauge clamps electrical, covering, and insulating tape level tool drill with drill bits plastic anchors tapping screws hole saw polyurethane foam flexible flanges Installing An Indoor Air Unit 1. Choose an area on an interior wall inside of the home that is at least seven feet above the ground to mount the indoor air unit. Avoid areas where there is direct exposure to sunlight, heat, and gas. Make sure there is at least six inches of open space surrounding the top and bottom of the unit. 2. Use the level tool to check the position of the mounting plate to ensure that it is properly square. Use the drill to place holes for the plastic anchors for the mounting plate. Insert the anchors into the drill holes and use tapping screws to attach and secure the mounting plate to the wall. 3. Determine the length of pipe that is needed to reach the outside condenser unit from the inside of the home. Choose a location on the interior wall to drill or saw a three to four inch hole in the wall for the piping lines to run towards the exterior wall based on the hole on the mounting bracket. 4. To provide for proper drainage, the hole should slope down towards the exterior wall. After the hole is complete, place a flexible flange into the hole. 5. Inspect the electrical connections and components on the mini-split system. Use the manufacturer’s diagram to make sure that all wires and cables are properly connected to the appropriate terminals. 6. Run the piping from the indoor unit through the hole in the wall. Avoid bending the piping to prevent potential operations problems. Take a fourth inch length of PVC pipe and place a pipe cap on the interior end. Run the PVC pipe through the hole in the wall towards the exterior wall. Mesh the copper and drain pipes, along with the power cables together with electrical tape. Make sure the drainpipe is in the bottom position to enhance draining capabilities. 7. Attach the pipe securely to the indoor air unit. This can be accomplished by using two wrenches and working them in opposite directions at the same time to tighten the connectors. Attach the water drainpipe to the indoor air unit’s base. Run the pipes and conduits through the hole in the interior wall towards the exterior wall. Double check the drainpipe to ensure that it is draining in an appropriate place. 8. Press the indoor air unit against the mounting plate and make sure it is secure. Installing An Outdoor Unit 1. Inspect the outside of your home to determine the best location to install the outdoor unit. Avoid areas where there is a high volume of traffic, dirt, debris, heat or exposure to weather elements such as rain and snow. There should be at least one foot of open and clear space surrounding the outdoor unit. To prevent electrical or radio wave interference, make sure that there are no television or radio antenna within 10 feet of your outdoor unit. 2. Choose a level area on the ground to place the concrete pad for the outdoor unit. Consider a height that will keep the outdoor unit from being covered in snow during the wintertime. 3. To minimize movement and vibrations, place rubber cushioning on top of the concrete pad before placing the outdoor unit on top of the pad. 4. Once in place, remove the cover on the outdoor condenser. Use the wiring diagram to aid you in connecting the electrical wires. Once the wires are properly connected, secure the cables with cable clamps and reattach the cover to the outdoor unit. Pay extra attention to the pipe flare nuts on the pipes. 5. To bleed the refrigerant lines, you need to remove the humidity and air from them. Remove the caps from the two and three-way valves and service port to attach the vacuum pump hose. Run the vacuum pump until it has reached the reading of 10mm Hg. Before turning off the vacuum pump, it is important to close the low-pressure knob first. Inspect the lines and valves for leaks. Remove the vacuum pump and replace all caps on the valves and ports. 6. Wrap all piping joints with covering and insulating tape. Secure the piping to the wall with clamps to prevent them from being in the way or disturbed. Fill the drilled holes in the interior and exterior walls with polyurethane foam to complete the installation process. Please Note: To prevent potential issues with safety and operation, consider hiring a professional to install your mini-split system. Professional installation will keep your manufacturer’s warranty active and keep you from having to deal with expensive repairs to correct any DIY mistakes you may have made.
dan says August 16, 2016 at 7:28 am Installing indoor unit- you are confusing the reader when you say to install on an interior wall. Interior walls refer to the dividing walls inside a home. Exterior walls refer to the perimeter walls. You should say perimeter wall (exterior). Reply
Robert Alexander says February 12, 2017 at 8:15 am Why not an interior wall.if it’s more convenient,what’s the difference.Splitting hairs? Reply
Tony Espo says June 15, 2017 at 11:07 pm Can the compressor be put in a large attic with plenty of air space???? This way it wont go to far from the cooling element in the room just below…. Reply
James Doyle says August 31, 2017 at 6:31 pm what would I have too do too expand a Fujitsu single unit Reply
HVAC tech says October 8, 2017 at 7:20 pm The compressor is located in the condenser unit or as the author refers to it the outdoor unit. The purpose is to expel the heat picked up from inside the space to be conditioned. Therefore it could not and should not be mounted indoors, in confined spaces or in an attick or crawl space. Reply
HVAC tech says October 8, 2017 at 7:24 pm Installing a mini split unit on an interior wall is difficult because it requires a place for the drain line to run to as such it’s not the most advisable location for on unless the design of the home has some sort of chase for which to adequately run the refrigerant lines and most importantly the drain. Done improperly will cause water to back up and spill out of the unit quickly destroying interior components of the home. I’ve seen it destroy drywall electrical even hardwood floor in a matter of a few days when gone unnoticed. So if is a matter of important clearification and not just splitting hairs. Reply
Barb Loiacona says March 7, 2018 at 12:47 pm what causes black particles to fly out of unit when turned on? In my office I have a unit and we clean the filters but you can see black up inside the unit? Reply
HVAC tech says October 8, 2017 at 7:31 pm In order to explains a Fujitsu single zone system, you would need to make sure that your condenser unit has additional ports and is sized by BTUs to handle the load from additional air handlers. Example: 9k btu and a 9k condenser unit. Cannot be expanded. If you had a 9k air handler on a 30k condenser you could add two more 9ks equalling 27k BTU or a 12k and a 7k. All of which needs to not exceed the BTU Rating of the condenser unit. Otherwise the air handles will not be able to remove heat efficiently and spaces will not cool. Most commonly when single zones are installed they are sized as such therefore a larger condenser unit will have to be purchased along with whatever size air handlers you would need. I hope my posts shed a little more light on these systems and help. Reply
Suzanne says December 16, 2017 at 4:19 am Can you explain why you say the inside unit must be 7 feet above the ground. I’ve just seen a post where they were recommending 18″ from the floor. What drives the decision about placement of inside and outside units? Reply
James Wall says April 1, 2018 at 5:23 pm I just bought a 12000 btu unit, i have not installed it yet but have been watching videos and reading paper work and my paper work says 90 inches from floor, I have a friend who is licensed , so I will pay him to do it right rather than me screw something up Reply
Charlie says May 31, 2018 at 3:31 pm Is there a maximum distance from the in door unit and the compressor? Reply
Nam says June 4, 2018 at 10:53 am Would 7ft height work for all climates? What height would you recommend for extremely cold location like Niagara Falls NY? Reply
Yvette Saenz says October 5, 2018 at 11:38 am We had a CIAC mini split installed in an addition. We have the inside unit turned off and put the the outside unit near our bedroom window. We hear it turn on like if a fan or something is running. Is this normal even though the unit is not powered on? Reply
