it's blowing air but it's not cold at all, just slightly cool, on the highest cool setting.

Diagnosis

The LG LP1419IVSM utilizes a Dual Inverter compressor designed to modulate speed for efficiency. When the unit blows air that is only "slightly cool" despite being on the highest setting, it indicates a failure in the heat exchange cycle. While the blower fan is functioning (moving air), the refrigerant is not absorbing heat from the room or discharging it effectively to the outside. The most common root cause for this specific model is a restriction in the exhaust airflow or a physical compromise of the internal refrigerant lines. Because this is a portable unit, the refrigerant lines are integrated into the chassis; however, if the unit was tilted during transport or if the exhaust hose is severely kinked, the compressor can overheat and trip a thermal overload protector. This shuts down the cooling cycle while leaving the fan running. Alternatively, a buildup of organic debris and dust on the evaporator coils (the front mesh) prevents the unit from pulling enough warm air across the coils, resulting in air that feels lukewarm. You can confirm this by checking if the exhaust air coming out of the hose is scorching hot; if the exhaust air is cool but the room air is also cool, the compressor is not engaging.

How to Fix It

To restore full cooling capacity, you must ensure the thermodynamic loop is unobstructed and the compressor is not in a thermal lockout state.

1. Hard Power Reset: Unplug the unit from the wall outlet completely. Wait exactly 10 minutes. This allows the internal capacitors to discharge and resets the Dual Inverter control board, clearing any "soft" compressor lockout errors.
2. Exhaust Hose Optimization: Detach the exhaust hose from the window kit. Inspect the plastic ribbing for any collapses or sharp 90-degree kinks. Ensure the hose is extended to its maximum length without being stretched tight. A compressed hose creates backpressure that prevents the condenser from shedding heat, forcing the compressor to shut off.
3. Filter Deep Clean: Remove the intake filters from the rear of the unit. Wash them with lukewarm soapy water and let them air dry completely. Use a vacuum with a brush attachment to gently clear the aluminum fins of the evaporator coil located behind the filters.
4. Ventilation Clearance: Ensure there is at least 20 inches of open space around the sides and rear of the unit. If the unit is pushed too close to a wall, it will recirculate its own hot air, causing the inverter to throttle down the cooling output to prevent overheating.
5. Re-Initialization: Plug the unit back in and set it to "Cool" mode, 60°F (16°C), with the fan speed set to High. Wait 5 minutes for the inverter compressor to ramp up to full speed.

If That Didn't Work

• Check for Refrigerant Leaks: Inspect the base of the unit for any oily residue. Refrigerant is mixed with oil; a shimmering, greasy spot on the plastic casing often indicates a puncture in the copper tubing. If you hear a faint hissing sound while the unit is powered on, the sealed system has been breached, and the unit will require a professional recharge or replacement.
• Capacitor Failure: If the fan is blowing but you never hear the distinct "hum" or "click" of the compressor starting, the start capacitor may have failed. This is a common failure point in high-efficiency inverter units. A technician can test the capacitor using a multimeter to see if it is holding the rated microfarads (µF).
• Sensor Malfunction: The internal thermistor (temperature sensor) may be reading the room temperature incorrectly, telling the inverter that the target temperature has already been reached. Try switching the unit to "Dry" mode for 30 minutes to see if the compressor engages; if it does, the temperature sensor is likely faulty.
• Drainage Blockage: Check the internal water tray. If the unit is full of water and the auto-evaporation system is failing, the unit may enter a protection mode. Drain the unit completely using the lower drain plug into a shallow pan.

Heads Up

• Avoid Tilting: Never lay this unit on its side or tilt it more than 15 degrees during operation. Doing so can cause refrigerant oil to migrate into the evaporator, blocking the flow and permanently damaging the Dual Inverter compressor.
• Hose Insulation: The exhaust hose radiates heat back into the room. To improve cooling efficiency, wrap the exhaust hose in a reflective thermal sleeve or insulating fabric to keep the heat moving outward.
• Avoid "Eco" Mode for Initial Cooling: When trying to cool a hot room, avoid using "Eco" or "Energy Saver" modes initially, as these modes cycle the compressor off more frequently to save power, which can make the air feel lukewarm.
• Seasonal Storage: Before storing the unit for winter, run the "Fan Only" mode for 2 hours to completely dry the internal coils and prevent mold growth that restricts airflow.