The MRCOOL Ductless Mini Split Heat Pump

The MRCOOL Ductless Mini-Split is the only whole-home mini-split solution that you can install yourself. This system provides simple, easy air comfort in up to four zones. The heat pump features:

• Easy DIY Installation
• Pre-charged DIY
• Quick Connect Line Set
• Simple to Use
• Multi-room Comfort
• Energy Efficient DC Inverter
• 100% Sealed System
• Gold Fin Condenser
• Eco Safe R-410A Refrigerant
• Smartphone App Controls
• Lifetime Technical Support
• Follow Me Feature
• Low Ambient Cooling

There are nine main steps covered in this guide that take place both inside and outside your home. For a more detailed guide, make sure you have a copy of the MRCOOL Installation & Owner’s Manual. Installing the MRCOOL DIY  does not require specialized tools or training. It does require basic technical skills. You are assuming the risk by handling materials containing refrigerants under pressure including that if not handled properly, refrigerant can cause bodily injury. If you do not feel comfortable conducting this installation process yourself, we recommend you retain the services of a qualified HVAC professional.

Installing the 3RD GEN MRCOOL Ductless Mini Split Heat Pump

1. Selecting an Installation Location for the Inside Unit

1. 1. Locate the cardboard wall template.
   2. Place the template on the wall at the installation location.
   3. Use the template to mark the location of the drill points for the mounting screws and wall hole. Make sure that the drill points for the mounting screws are located on wall studs.
   4. Remove the template.

2. Attaching the Mounting Plate to the Wall

1. Drill screw holes at the indicated points into the wall studs.
2. Remove the mounting bracket from the rear of the interior air handler by removing the screws holding it in place.
3. Screw the metal bracket to the wall according to the template.
4. Use a level to ensure the mounting plate is flush and level.

3. Drilling the Hole for Connective Piping

1. Drill a 3.5 inch diameter hole through the wall, at a slightly downward angle (to ensure proper drainage), to accommodate the line set, condensate drain line and communication cable to the exterior condenser.
2. Carefully bend piping at the back of the air handler until it is sticking straight out from behind the unit.
3. Using electrical tape, lightly tape the refrigerant piping & condensate drain line at the back of the indoor unit into a bundle (this will make it easier to pass through the wall hole). The drain pipe MUST be on the bottom. DO NOT wrap the end of the piping (connectors & drain hose) you will need access to them for later steps.
4. Insert wall hole sleeve into wall hole.
5. Push the wires and piping bundle through the wall hole.
6. Snap the air handler onto the wall bracket by leaning the top towards the wall and hooking it on the top of the bracket. Then, apply pressure to the bottom half to snap it to the bracket.

4. Selecting an Installation Location for the Outside Unit

1. Place the outside condenser unit firmly on the ground or attach it to a secure metal wall bracket or pad. A drain pipe underneath the unit is not required unless the unit is elevated. Please refer to the manual for more information.
2. Install the wall hole finishing cap/seal. Then, carefully bend the piping coming out of the wall hole (from the indoor unit) down towards the wall.
3. Remove the plastic seals from the indoor handler refrigerant lines.
4. Carefully unroll one end of the Quick Connect line set*. Only unroll the amount needed to connect to the indoor handler fittings. Leave the remainder coiled.
5. Align the Quick Connect refrigerant lines to the matching indoor handler fittings. Tighten the first few threads by hand.
6. Using two open-ended wrenches, or crescent (adjustable-type) wrenches, and the image below as a guide: place the wrenches on points marked “1” & “2,” only turning the nut at the point marked “2.” Ensure that the screw connector does not become crooked while working quickly to tighten it. Tighten the connector until snug.
7. Then, tighten the connector slightly beyond that point to apply torque to the connector. Repeat the same steps for the second line. Please refer to the manual for information about torque requirements for the connectors.

5. Connecting the Line Set to the Outside Unit

1. Carefully roll the excess tubing and place it behind the condenser, lying flat on the ground. 
2. Align the line set connectors to the outside condenser and tighten the first few threads by hand. NOTE: Make sure the piping connection to the outside unit has plenty of slack and the line set is not stressed.
3. Using two open-ended wrenches, or crescent (adjustable-type) wrenches, and the image below as a guide: tighten the bottom screw connector. Place wrenches on points marked “1” & “2,” only turning the nut at the point marked “2.” Ensure the screw connector does not become crooked as you work quickly to tighten it. Tighten the connector until it is snug. 
4. Then, tighten the connector slightly beyond that point to apply torque to the connector. Please refer to the manual for information about torque requirements. Repeat the same steps for the top screw connector. 

6. Connecting the Line Set to the Indoor Unit

1. Starting with the top valve, using an open-ended wrench, or crescent (adjustable-type) wrench, remove the brass cap from the valve on the outside unit. 
2. Then, insert a 5 mm Allen wrench to open the valve by turning it counter-clockwise until it stops turning. DO NOT force it. NOTE: When opening the valves you may hear a soft hissing sound as a slight amount of R-410a refrigerant exits the condenser. 
3. Reinstall the cap and tighten securely. Then, repeat the same steps for the bottom valve. 
4. Now you will perform the same action for the two Main Valves (King Valves) after all other valves have been opened.
5. Using soapy water (in a spray bottle or with a brush), or leak detection spray, apply to the Quick Connect fittings at the indoor air handler and outdoor condenser to check for leaks. If you see bubbles begin to form, this indicates there is a leak. If so, re-tighten the connection accordingly until the bubbles are gone. Please refer to the manual for more detailed information on checking for leaks. 

7. Setting Up Electrical Connections

1. Remove the electrical cover by removing the screws holding it in place. 
2. Wires and terminals that are numbered should be matched and connected accordingly. 
3. Terminal L1(A) of the outdoor unit must connect with terminal 1 on the indoor unit. Continue to match zone to zone for any additional connections. 
4. Replace electrical cover and screw it back into place. Refer to the diagrams / photo at the bottom left. 

For more detailed instructions regarding the electrical connections, please refer to the Installation Manual.

8. Wrapping the Piping Connections

1. Pack the wall hole with the supplied Neoprene (or Spray Foam), filling any space not taken up by the piping & lines, in order to seal the hole. 
2. To protect Quick Connect connections and reduce vibration, wrap them with the black sound deadening pads. Then, install the white pipe insulation over the pads. 
3. Now, starting at the outdoor condenser and working your way up to the wall hole, you will wrap the exposed line set, cables, and drain hose together tightly using the supplied Non-adhesive U.V. tape. The drain pipe will need to be at the bottom of the bundle. Refer to the diagram on the previous page. DO NOT wrap the end of the drain hose. 
4. To further improve overall appearance and long-term durability of the line set, it is recommended to install an optional MRCOOL LineGuard (sold separately).

9. Setting Up Remote Access

1. Install the provided batteries into the remote control.
2. Press the Power button on the remote control.
3. The MRCOOL DIY Series should activate automatically.
4. To use the MRCOOL Smartphone App, refer to the Smart Controller Module instructions included in the box.

We hope you found our installation guide for the MRCOOL Ductless Mini-Split Heat Pump helpful. Please refer to the MRCOOL Installation & Owner’s Manual for a more detailed guide.