LG LMU363HV Installation Manual

The LG LMU363HV is a high-efficiency, multi-zone mini-split air conditioning system designed for residential and light commercial use. This manual provides essential information for the safe and proper installation of the indoor and outdoor units, including electrical connections, refrigerant piping, drainage setup, and final commissioning. Following these instructions is crucial for optimal performance, warranty validation, and user safety.

1. Safety Precautions 2. Package Contents & Inspection 3. Unit Specifications 4. Selecting Installation Location 5. Installing the Indoor Unit 6. Installing the Outdoor Unit 7. Refrigerant Piping Connection 8. Electrical Wiring 9. Drainage System Installation 10. Vacuum Drying & Leak Test 11. Final Check & Commissioning

Safety Precautions

Before installation, read all safety warnings. Installation must be performed by a qualified technician in accordance with national and local electrical and construction codes.

Symbol	Meaning	Instruction
WARNING	Risk of death or serious injury	Disconnect all power before servicing. Use proper personal protective equipment (PPE).
CAUTION	Risk of minor injury or product damage	Do not install near heat sources or flammable gases. Handle refrigerant piping with care to avoid kinks.
NOTE	Important information	Keep the manual for future reference. Ensure the installation site can support the unit's weight.

WARNING! Incorrect installation can cause electric shock, fire, or equipment failure. Always use the specified cables and components.

Package Contents & Inspection

Unpack all components carefully and verify against the packing list.

Indoor Unit: Wall-mounted evaporator unit.
Outdoor Unit: Condenser unit.
Remote Control & Batteries: For system operation.
Installation Kit: Includes mounting plate, screws, pipe cover, drainage hose, and communication cable.
User Manual & Warranty Card: Documentation.

Inspect for any shipping damage. Report any missing or damaged parts to the carrier and your supplier immediately. Do not proceed with installation if components are damaged.

Unit Specifications

Model: LMU363HV
Type: Multi-Zone Mini-Split Heat Pump
Cooling Capacity: 36,000 BTU/H
Heating Capacity: 36,000 BTU/H
Power Supply (Outdoor Unit): 208/230V, 1 Phase, 60Hz
Max. Current: 20.5 A
Refrigerant Type: R-410A
Refrigerant Charge (Factory): See nameplate
Operating Temperature (Cooling): 64°F to 115°F (Outdoor)
Sound Level (Indoor): As low as 19 dB(A)
Net Weight (Outdoor Unit): Approx. 110 lbs

Selecting Installation Location

Choose locations that ensure efficient operation, easy maintenance, and minimal noise disturbance.

Indoor Unit Location:

Install on a sturdy wall that can support the unit's weight (over 55 lbs).
Ensure at least 7 feet from floor to unit bottom for optimal air circulation.
Keep at least 6 inches from ceiling and 20 inches from side walls.
Avoid direct sunlight, heat sources, and areas with high humidity or oil mist.
Ensure condensate can drain freely.

Outdoor Unit Location:

Place on a solid, level base (concrete pad or mounting brackets).
Provide ample clearance: at least 20 inches at front (fan side), 12 inches at back and sides.
Ensure good ventilation; avoid enclosed spaces.
Protect from direct snowfall, dripping water, and strong wind.
Consider noise direction away from bedrooms and neighbors.

CAUTION! The outdoor unit is heavy. Use proper lifting equipment and at least two people for handling.

Installing the Indoor Unit

Secure the mounting plate to the wall first, then hang the indoor unit.

Position the Mounting Plate: Use the plate as a template. Mark hole locations on the wall. Ensure the plate is perfectly level.
Drill Holes & Install Anchors: Drill holes for the mounting screws and, if needed, for the piping/drainage (a 2.5-inch hole is typical). Install wall anchors for solid mounting.
Secure the Plate: Fasten the plate to the wall using all provided screws.
Prepare Piping & Cables: Route the refrigerant pipes, drain hose, and communication cable from the outdoor location through the wall hole. Leave sufficient slack (approx. 12 inches) behind the unit.
Hang the Indoor Unit: Hook the top of the indoor unit onto the upper edge of the mounting plate. Press the bottom until it clicks into place.

NOTE: The drain hose must have a continuous downward slope (at least 1/100 gradient) for proper water flow.

Installing the Outdoor Unit

The outdoor unit must be installed on a stable, vibration-absorbing base.

Prepare the Base: Use a concrete pad or vibration-absorbing mounting brackets. The base must be level and capable of supporting the unit's weight.
Position the Unit: Carefully place the outdoor unit on the base using a hand truck or lift. Do not drag the unit.
Secure the Unit (if required): In areas with high wind or seismic activity, secure the unit to the base using anchor bolts or anti-vibration pads as per local codes.
Ensure Clearance: Verify all required clearances for airflow and service access are met.

WARNING! Never install the outdoor unit in a location where flammable gas could leak or accumulate.

Refrigerant Piping Connection

Proper piping is critical for system efficiency and longevity. Use only clean, dehydrated, copper piping designated for R-410A.

Cut & Deburr Pipes: Cut the piping to the required length using a pipe cutter. Remove all burrs from the inside and outside.
Flare the Pipe Ends: Use a precision flaring tool to create a perfect 45-degree flare on both the liquid and gas pipe ends. Apply a small amount of refrigeration oil to the flare surface.
Connect to Indoor Unit: Connect the liquid (smaller) and gas (larger) pipes to the corresponding valves on the indoor unit. Tighten the flare nuts with a torque wrench to the specified value (typically 18-22 ft-lb).
Route Pipes to Outdoor Unit: Insulate both pipes and the drain hose together with the provided tape. Route the bundle to the outdoor unit, avoiding sharp bends (minimum bend radius is 4 inches).
Connect to Outdoor Unit: Connect the pipes to the service valves on the outdoor unit. Tighten with a torque wrench to specification.

CAUTION! Never use old refrigerant piping or piping used for other refrigerants. Moisture or contamination will damage the system.

Electrical Wiring

All electrical work must comply with the National Electrical Code (NEC) and local regulations. A dedicated circuit is required.

Power Off: Ensure the main power disconnect switch is in the OFF position.
Connect Outdoor Power: Run the dedicated power cable from the main disconnect to the outdoor unit's terminal block (L1, L2, Ground). Use copper wire of the correct gauge (refer to manual table). Secure the cable with the strain relief.
Connect Communication Cable: Run the shielded communication cable (provided) between the indoor and outdoor units. Connect to the designated terminals on both PCBs. Ensure polarity is correct.
Connect Indoor Power (if required): Some models power the indoor unit from the outdoor unit via the communication cable. Verify your model's requirements.
Secure All Connections: Ensure all terminal screws are tight and no stray wires are present. Replace all electrical covers.

WARNING! Incorrect wiring can cause electric shock or fire. The unit must be properly grounded.

Drainage System Installation

Proper drainage prevents water leakage and damage.

Attach Drain Hose: Connect the flexible drain hose securely to the indoor unit's drain pan outlet. Use a hose clamp.
Route the Hose: Route the hose along with the refrigerant pipes, maintaining a continuous downward slope toward the drain point. Do not create traps or sags.
Terminate the Drain: Drain to a suitable location such as a floor drain, condensate pump, or outdoors. If draining outdoors, use a drain extension kit to prevent water from splashing on the wall.
Insulate (if needed): In unconditioned spaces, insulate the drain hose to prevent condensation.

Tip: Perform a simple water test by pouring a small amount of water into the indoor unit's drain pan to verify flow.

Vacuum Drying & Leak Test

This step removes air and moisture from the refrigerant circuit, which is essential for system life and performance.

Connect Manifold Gauge & Vacuum Pump: Connect the center hose of a manifold gauge set to a high-capacity vacuum pump. Connect the low and high-side hoses to the service ports on the outdoor unit's valves.
Open Service Ports: Ensure both the liquid and gas service valves on the outdoor unit are in the closed (front-seated) position. Open the caps on the service ports.
Evacuate: Start the vacuum pump. Open the low and high-side valves on the manifold gauge. Evacuate the system to a vacuum of at least 500 microns (0.5 Torr). Hold for 15-20 minutes to ensure no rise in pressure (indicating no leaks or moisture).
Close & Isolate: Close the manifold gauge valves. Turn off the vacuum pump. Wait for 5 minutes to check if the vacuum holds stable.
Charge Refrigerant (if needed): If the pre-charge is insufficient for the piping length, add the precise amount of R-410A in liquid form into the liquid line port. Refer to the manual for required additional charge based on pipe length.

NOTE: A proper vacuum is critical. Moisture left in the system will cause acid formation and compressor failure.

Final Check & Commissioning

Complete the installation by opening the valves, checking operation, and instructing the user.

Step	Action	Expected Result
1	Open Service Valves	Use a hex wrench to fully open the liquid and gas service valves on the outdoor unit. This releases refrigerant into the system.
2	Power On	Turn on the main power disconnect and any branch circuit breakers.
3	Test Operation	Use the remote to turn on the system in Cooling and Heating modes. Check for proper airflow, cooling/heating effect, and unusual noises.
4	Check Drainage	Verify water is flowing from the drain hose during cooling operation.
5	Final Inspection	Ensure all covers and panels are installed, all connections are tight, and the installation site is clean.
6	User Instruction	Explain basic operation, filter cleaning, and routine maintenance to the end-user. Provide the user manual.

Record Installation: Complete the installation checklist and warranty registration. Keep a copy for your records.

For Technical Support: Contact LG Electronics at 1-800-243-0000 or visit www.lg.com.