LG LMU361HHV Installation Manual

The LG LMU361HHV is a high-efficiency multi-zone outdoor condensing unit designed for residential and light commercial applications. This manual provides essential information for the safe and proper installation, setup, operation, and maintenance of the unit. It is crucial that all installation procedures are performed by qualified HVAC technicians in accordance with local codes and regulations.

Safety Precautions

Before installation, read all safety warnings. Failure to follow these instructions can result in serious injury, death, or equipment damage.

Unit Specifications

• Model: LMU361HHV
• Type: Multi-Zone Outdoor Condensing Unit
• Power Supply: 208-230V, 1 Phase, 60Hz
• Max. Connected Indoor Units: Up to 5 zones
• Refrigerant Type: R410A
• Operating Ambient Temp: -13°F to 122°F (-25°C to 50°C)
• Sound Pressure Level: ≤ 65 dB(A)
• Net Weight: Approx. 220 lbs (100 kg)
• Dimensions (HxWxD): 43" x 35" x 15" (1092 x 889 x 381 mm)

Pre-Installation Checklist

1. Verify the model number matches the installation plan.
2. Inspect the unit for any shipping damage. Report any damage immediately.
3. Ensure all required tools and materials are available (torque wrench, flaring tool, vacuum pump, manifold gauge, etc.).
4. Check that the installation site meets all location requirements (clearance, foundation, etc.).
5. Review the electrical service requirements and ensure adequate power is available.

WARNING! Do not proceed with installation if the unit is damaged or if site conditions are not met.

Installation Location Requirements

Select a location that ensures optimal performance, serviceability, and safety.

1. Clearance: Maintain minimum clearances: 20" (500mm) from walls or obstacles on air intake side, 40" (1000mm) on air discharge side, and 12" (300mm) overhead for service access.
2. Foundation: Install on a solid, level concrete pad or reinforced mounting frame. Ensure it can support the unit's weight.
3. Environment: Avoid locations with excessive dust, leaves, salt air, or corrosive gases. Ensure good air circulation and drainage.
4. Noise Consideration: Position away from windows of adjacent properties to minimize noise disturbance.
5. Protection: Do not install where snow accumulation or direct runoff from roofs could block airflow.

Mounting the Outdoor Unit

1. Place the vibration-absorbing pads (supplied) on the prepared foundation.
2. Carefully lift and position the unit onto the pads using a hoist or sufficient manpower.
3. Use a level to ensure the unit is perfectly level in all directions. Shim if necessary.
4. Secure the unit to the foundation using anchor bolts (not supplied) to prevent movement in high winds.
5. Remove all protective films and shipping braces from the service valves and compressor.

CAUTION! An unlevel installation can cause abnormal vibration, noise, and improper drainage.

Refrigerant Piping Connection

Use only clean, dehydrated, phosphorus-deoxidized copper tubing (ASTM B280) of the specified diameter.

1. Route piping from the indoor units to the outdoor unit location. Keep runs as short and straight as possible.
2. Cut tubing to length with a pipe cutter. Deburr the inside and outside edges.
3. Flare the pipe ends using a precision flaring tool to create a perfect 45° flare. Apply a small amount of refrigerant oil to the flare surface.
4. Connect the gas (larger) and liquid (smaller) lines to the corresponding service valves on the outdoor unit. Hand-tighten the flare nuts first.
5. Using a torque wrench, tighten the flare nuts to the specified torque (typically 18-22 ft-lb / 25-30 Nm for 3/8" liquid line).
6. Insulate both refrigerant lines separately with closed-cell foam insulation to prevent condensation.

Electrical Wiring

All electrical work must comply with NEC (National Electrical Code) and local regulations.

1. Run a dedicated power supply circuit from the main electrical panel to a disconnect switch near the outdoor unit.
2. Connect the power wires (L1, L2, Ground) from the disconnect to the terminal block inside the unit's electrical compartment. Follow the wiring diagram on the unit's service panel.
3. Connect the communication wiring (shielded 2-conductor cable, 18 AWG) between the outdoor unit and each indoor unit as per the system wiring diagram.
4. Ensure all connections are tight and secure. Use conduit and strain relief as required.

WARNING! Incorrect wiring can cause component failure, fire, or electric shock. Verify polarity and phase.

Vacuum Drying & Leak Test

This critical step removes moisture and non-condensable gases from the system.

1. Connect a high-capacity vacuum pump and manifold gauge set to the service ports.
2. Open the low and high-side gauge valves. Start the vacuum pump.
3. Evacuate the system to a level of 500 microns or less. Hold the vacuum for at least 15 minutes to ensure no rise (indicating a leak or moisture).
4. Close the gauge valves and turn off the pump. Perform a standing vacuum test for another 15 minutes.
5. If the vacuum holds, close the service valves on the outdoor unit using a hex wrench. Disconnect the vacuum pump.
6. Perform a leak check on all flare and brazed connections using an electronic leak detector or soap bubbles.

Initial System Setup & Commissioning

1. Slowly open the liquid and gas service valves on the outdoor unit fully (back-seat them).
2. Restore power to the outdoor unit and all connected indoor units.
3. Using the installer settings on the remote controller or a dedicated service tool, set the system parameters:
   • Set the correct number of connected indoor units.
   • Assign addresses to each indoor unit if required.
   • Configure optional settings (thermostat type, fan delay, etc.).
4. Start the system in cooling mode. Check operation of each indoor unit.
5. Measure and record system operating data: Suction pressure, discharge pressure, superheat, subcooling, and line temperatures. Compare to specifications.
6. Instruct the end-user on basic remote control operation and filter maintenance.

Maintenance Guidelines

Regular maintenance ensures efficiency, longevity, and safe operation.

• Monthly: Visually inspect the unit for debris, corrosion, or refrigerant leaks. Clean the area around the unit.
• Seasonal (Start of Cooling/Heating Season):
  • Clean the outdoor coil fins with a soft brush and low-pressure water spray (with power OFF). Straighten any bent fins.
  • Check electrical connections for tightness and signs of overheating.
  • Check and clean the indoor unit filters (user maintenance).
• Annual (Professional Service): Comprehensive check of refrigerant charge, compressor amperage, fan motor operation, and control board functions.

CAUTION! Always disconnect power before performing any maintenance.

Troubleshooting

Reset: Power cycle the unit (turn off at disconnect, wait 5 minutes, turn back on).

Service: For persistent issues, contact LG Customer Support at 1-800-243-0000 or visit www.lg.com.