LG LP123HD3B Service Manual

The LG LP123HD3B is a high-performance portable air conditioner unit designed for residential and light commercial use. This service manual provides comprehensive information for qualified service technicians, including technical specifications, system diagrams, component locations, troubleshooting procedures, disassembly/assembly instructions, and safety precautions. Below are key sections for safety, features, installation, service procedures, and technical data.

Features at a Glance

Key components: High-efficiency rotary compressor, cross-flow fan, electronic control board, dual-layer air filter, auto-swing louvers, 24-hour timer, remote control, and multiple operating modes.

Safety Precautions

Before servicing, disconnect power and discharge capacitors. Use proper tools and PPE.

1. Electrical Safety: Always unplug the unit before accessing internal components. Verify capacitor discharge with a proper meter.
2. Refrigerant Safety: Follow EPA Section 608 guidelines. Use recovery equipment. Do not vent R410A.
3. Mechanical Safety: Secure the unit during disassembly. Beware of sharp edges on chassis and coils.
4. Fire Safety: Keep away from flammable materials. Check wiring for damage or overheating.

WARNING! Only qualified personnel trained in HVAC/R and familiar with R410A should perform service. Failure to follow safety procedures can result in electric shock, refrigerant burns, or fire.

Installation Guidelines

Proper installation is critical for performance and safety.

1. Location: Place on a flat, stable surface near a window or vent opening. Ensure at least 20 inches of clearance on all sides for airflow.
2. Venting: Connect the exhaust hose securely to the unit and window kit. Ensure hose is straight and unobstructed.
3. Power: Plug directly into a dedicated 115V, 15A grounded outlet. Do not use an extension cord.
4. Condensate: For continuous operation in high humidity, attach the optional drain hose to the port.
5. Initial Test: After installation, run the unit in Cool mode for 15 minutes to verify operation and check for leaks.

CAUTION! The unit is heavy. Use two people for handling. Ensure the window seal kit is installed correctly to prevent hot air backflow.

Specifications

• Model: LP123HD3B
• Cooling Capacity: 12,000 BTU/h (ASHRAE)
• Power Consumption (Cooling): 1100 W (approx.)
• EER: 10.9
• Air Flow (High): 290 CFM
• Operating Voltage Range: 104V ~ 127V
• Refrigerant Type/Charge: R410A, 15.9 oz (450g) ± 5%
• Compressor Type: Rotary, Hermetic
• Unit Dimensions (HxWxD): 17.1" x 13.8" x 28.3"
• Net Weight: 68 lbs (30.8 kg)
• Operating Ambient Temp: 64°F ~ 95°F (18°C ~ 35°C)

Controls and Functions

Control Panel (LED Display): POWER, MODE, FAN SPEED, TEMP ▲/▼, TIMER, SLEEP, SWING.

Remote Control: POWER, MODE (Cool/Dry/Fan/Auto), TEMP SET, FAN SPEED, TIMER ON/OFF, SLEEP, SWING, FILTER RESET.

Functional Descriptions:
Cool Mode: Compressor and fan run to lower room temperature to set point.
Dry Mode: Runs at low fan speed to dehumidify.
Fan Mode: Only the indoor fan operates.
Auto Mode: Unit automatically selects Cool or Fan based on room temperature.
Timer: Can be set to turn unit ON or OFF after 1-24 hours.
Sleep Mode: Gradually adjusts temperature over 7 hours for comfort and energy savings.
Swing: Automatically moves vertical louvers for wide air distribution.

System Components & Diagrams

Major Components: Compressor, Condenser, Evaporator, Capillary Tube, Cross-flow Fan, Fan Motor, Control PCB, Thermostat, Filter.

1. Refrigeration Cycle Diagram: Shows flow of refrigerant (R410A) through compressor, condenser, capillary, evaporator.
2. Component Location Diagram: Identifies the physical location of all major parts within the chassis.
3. Air Flow Diagram: Illustrates path of room air through filter, evaporator, and back into room; exhaust air path through condenser and hose.

Tip: Refer to the exploded view diagram (Fig. 7-1 in manual) for part numbers and assembly relationships.

Disassembly & Assembly

Procedure to access internal components. Always disconnect power first.

1. Remove Cabinet: Remove all screws from rear and side panels. Carefully lift the main cabinet shell off the chassis.
2. Access Control Board: Located on the front upper section. Disconnect wire harnesses before removing PCB.
3. Remove Fan Assembly: Detach fan motor bracket screws and electrical connector. Lift fan and shroud out.
4. Access Compressor & Coils: Requires removal of insulation and refrigerant line access panels. Evacuate system first.
5. Reassembly: Reverse the procedure. Ensure all wiring is routed correctly and connectors are secure. Replace all foam seals.

WARNING! The evaporator and condenser fins are sharp. Wear cut-resistant gloves. Handle the capillary tube with care to avoid kinks.

Troubleshooting Flowcharts

Systematic approach to diagnose common failures.

Electrical Schematics

Detailed wiring diagram showing connections between:
- Main Power Cord
- Control PCB
- Compressor (with Run Capacitor)
- Indoor Fan Motor
- Thermostat/Sensors
- Display Board
- Remote Receiver

Component Values:
Run Capacitor: 25µF ±5%, 370VAC
Fuse: 250V, 10A (on PCB)
Thermistor (Room Temp): 10kΩ @ 25°C

CAUTION! Use a multimeter to verify voltages and continuity. Always compare readings to schematic values.

Refrigerant Handling

This unit uses R410A, a high-pressure HFC blend.

1. Recovery: Use a dedicated R410A recovery machine and cylinder. Recover all refrigerant before opening the sealed system.
2. Charging: Charge with liquid refrigerant into the high-side service port. Weigh the charge for accuracy. Do not use the "superheat" method common with R22.
3. Pressure/Temp: Typical operating pressures (at 80°F ambient): High Side: ~380-420 psi, Low Side: ~120-140 psi.
4. Leak Check: Use electronic leak detector or bubble solution. Common leak points: service valve stems, schrader cores, brazed joints.

WARNING! R410A operates at much higher pressure than R22. Use gauges and hoses rated for R410A (minimum 800 psi). Never mix refrigerants.

Error Codes & Diagnostics

The control board monitors system status. Faults are indicated by flashing LED patterns on the display.

Reset: Unplug unit for 5 minutes to clear temporary error codes. Persistent codes indicate a hardware fault.

Service Contact: For technical support or genuine LG parts, contact LG Electronics USA at 1-800-243-0000 or visit www.lg.com.