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Not Cooling - Room Air Conditioner

Troubleshooting Air Conditioners Last Updated 05/27/2017

When it’s hot outside, the last thing you want is for your air conditioner to stop cooling. Let's check a few things to see if we can quickly resolve the issue.

Before we get started, if the unit cools at night but not during the day, this indicates that the unit is cooling but experiencing a performance issue. Check our Cooling Tips section to enhance its performance.

  1. Select the type of air conditioner you have:

    Portable

    Window

    Through the wall

    Ductless / Split

  2. Do you see any error code on the display screen?

    Yes No
  3. Select the error code on your display:

    1. P2 or FL
    2. CH34
    3. E1 or CH02
    4. E2 or CH01
    5. E3 or CH03
    6. E4
    7. E5
    8. F1,F2, or F3

    If the error code on your unit is not listed here, refer to your owner's manual to resolve the model specific error code. Please visit our Documents and Manuals page to download a copy.

  4. Does the unit cool at night, but NOT during the day?

    Yes No
  5. If the unit cools properly during the night but not during the day, then the unit is working properly but we need to enhance its performance. Please visit our Cooling Tips section of this article.

  6. If hot air from outside is getting into the room through the vent, it will prevent the unit from cooling properly. Let's check the vent using the following steps:

    1. Inspect the end that connects to the air conditioner. It should be connected securely with no air escaping.

    2. Ensure that nothing is inside the vent, such as packing material or accessories for the air conditioner.

    3. Visually inspect the length of the duct for any holes or tears.

    4. There should be no extensions added to the exhaust duct because the fan is not strong enough for longer lengths.

    5. The vent should not be vented up through the ceiling. The humid air that is being exhausted may be too heavy to completely vent out.

    6. Finally, check the end of the hose and make certain that it is connected to the vent panel in the window securely, and the window is sealed properly.

    7. For more information, watch our Portable Air Conditioner - Installation video.

    duct

    If the unit is still not cooling, we need to test the compressor.

    Proceed to Compressor Test
  7. How to test the compressor:

    1. Unplug the unit for at least 30 seconds. Use a timer if necessary.

      Note: If the unit was not unplugged for at least 30 seconds, the unit's safety switch will prevent the compressor from turning on for 3 minutes.

    2. Plug the unit back in.

    3. Power the unit on.

    4. Adjust settings: COOL mode, lowest temperature, highest fan speed.

    5. Listen for the compressor, which may take up to 30 seconds to turn on.

      Note: You should hear the sound of the compressor initially engaging and then a steady humming that can be heard over the fan.

    Do you hear the compressor turn on?

    Yes No
  8. Hold a hand in front of the unit for two or more minutes.

    Does the air feel as if its cooling down?

    Yes No
  9. This unit will require a repair service, please visit our Request a Repair page.

  10. Great! The unit is cooling, but something is affecting its performance. For more information on how to maximize performance, visit our Cooling Tips section of this article.

  11. Is the outdoor temperature above 95°F?

    Yes No
  12. Extremely high temperatures will challenge the unit's performance. For more information on how to maximize performance, visit our Cooling Tips section of this article.

  13. The unit will require a repair service. Please visit our Request a Repair page.

  14. Do you see any error code on the display screen?

    Yes No
  15. Select the error code on your display:

    1. P2 or FL
    2. CH34
    3. E1 or CH02
    4. E2 or CH01
    5. E3 or CH03
    6. E4
    7. E5
    8. F1,F2, or F3

    If the error code on your unit is not listed here, refer to your owner's manual to resolve the model specific error code. Please visit our Documents and Manuals page to download a copy.

  16. Does the unit cool at night, but NOT during the day?

    Yes No
  17. If the unit cools properly during the night but not during the day, then the unit is working properly but we need to enhance its performance. Please visit our Cooling Tips section of this article.

  18. Check the FRESH AIR VENT.

    This vent opens a small vent in the center wall of the air conditioner to allow fresh, outside air, into the room. This is counter-productive to cooling. Keep this vent CLOSED always.

    Continue to Next Step
  19. Let's check the power supply.

    The unit requires 208/230 volts and 20 amps to operate properly; if this criteria is not met, this may affect the units performance.

    A few quick ways to identify if the unit does not have the appropriate power supply are:

    • when the outlet had to be changed to match the plug,

    • when an inverter or adapter is being used, or

    • if the fan will not change speeds when switching between high and low.

    Check the power requirements for the unit. Does the unit have the correct power supply?

    Yes No
  20. Then let's perform a quick compressor test to see if the compressor is working properly.

    1. Unplug the unit for at least 30 seconds. Use a timer if necessary.

      Note: If the unit was not unplugged for at lest 30 seconds, the unit's safety switch will prevent the compressor from turning on for 3 minutes.

    2. Plug the unit back in.

    3. Power the unit on.

    4. Adjust settings: COOL mode, lowest temperature, highest fan speed.

    5. Listen for the compressor, which may take up to 30 seconds to turn on.

      Note: You should hear the sound of the compressor initially engaging and then a steady humming that can be heard over the fan.

    compressor

    Do you hear the compressor turn on?

    Yes No
  21. There is a power supply problem that needs to be corrected. This may require the services of an electrician.

  22. Hold a hand in front of the unit for two or more minutes.

    Does the air feel as if its cooling down?

    Yes No
  23. The unit will require a repair service, please visit our Request a Repair page.

  24. Great! The unit is cooling but something is affecting its performance. For more information on how to maximize performance, visit our Cooling Tips section of this article.

  25. Is the outdoor temperature above 95°F?

    Yes No
  26. Extremely high temperatures will challenge the unit's performance. For more information on how to maximize performance, visit our Cooling Tips section of this article.

  27. The unit will require a repair service. Please visit our Request a Repair page.

  28. Split units and duct free air conditioners that are used in an office or industrial environment are considered business units and are not covered in this article, please visit LG Business - Air Conditioning Technologies.

When the unit is struggling to perform, often the cause is something small and easily overlooked. Let's check the following:

    • The unit must be sized for the space. If the unit is too small OR too big, it will not cool efficiently.

    • If the unit is too big it will short cycle, turning on and off repeatedly while not cooling the room effectively.


    • There must be at least 20 inches of open space around the unit.

    • To maximize airflow and cooling performance, place the portable air conditioner as close to the center of the room as possible.

    distance from wall
    • The air filter should be cleaned at least every 2 weeks. It may be necessary to do so more often, depending on the environment.

    • The number of filters will vary by model. Some models can have up to four filters, one at the top and one at the bottom, and one on each side of the air conditioner. Be sure to clean both of them regularly.

    change air filter
    • Don't turn the unit off during the day, but rather just raise the temperature. This will allow the unit to maintain a more stable temperature, and allow it to cool more efficiently once the temperature setting is decreased.

When the unit is struggling to perform, often the cause is something small and easily overlooked. Let's check the following:

  • Bigger is not better! The air conditioner must be sized properly for the space it is cooling.

    • If the unit is too big it will short cycle, turning on and off repeatedly while not cooling the room effectively.

    • If the unit is too small, it will not cool as efficiently.


    • Don't turn the unit off during the day, but rather just raise the temperature. This will allow the unit to maintain a more stable temperature, and allow it to cool more efficiently once the temperature setting is decreased.

    • If the air conditioner is exposed to direct sunlight, put some shade on it!

    • If exposed to direct sunlight, the air conditioner will get very hot and have difficulty discharging the heat. It may be necessary to cover the unit with an awning.

    ..
  • Clean the Air Filter

    The air filter should be cleaned at least every 2 weeks. It may be necessary to do so more often, depending on the environment.

    ..

    Clean the OUTSIDE Coils

    • Dust, pollen, and other environmental particulates buildup on these coils, and prevent proper cooling.

    • Use a garden hose and bristled brush to gently clean the coils. Or, you can check your local hardware store for air conditioner coil cleaner. Some cleaners are no rinse, so just spray it on and let it do its job.

    • ..

When the unit is struggling to perform, often the cause is something small and easily overlooked. Let's check the following:

    • Bigger is not better! The air conditioner must be sized properly for the space it is cooling. A unit that is too big will not cool as efficiently.

    • If the unit is too big it will short cycle, turning on and off repeatedly while not cooling the room effectively.

    • ..
  • Don't turn the unit off during the day, but rather just raise the temperature. This will allow the unit to maintain a more stable temperature, and allow it to cool more efficiently once the temperature setting is decreased.

    • If the air conditioner is exposed to direct sunlight, put some shade on it!

    • If exposed to direct sunlight, the air conditioner will get very hot and have difficulty discharging the heat. It may be necessary to cover the unit with an awning.

    ..
  • Clean the Air Filter

    The air filter should be cleaned at least every 2 weeks. It may be necessary to do so more often, depending on the environment.

    ..

    Clean the OUTSIDE Coils

    • Dust, pollen, and other environmental particulates buildup on these coils, and prevent proper cooling.

    • Use a garden hose and bristled brush to gently clean the coils. Or, you can check your local hardware store for air conditioner coil cleaner. Some cleaners are no rinse, so just spray it on and let it do its job.

    • ..

CH34 Error Code

This code displays when the SAFETY RELAY causes the unit to power down due to abnormal pressure in the sealed system. This is not a defect, but designed to protect the unit from overheating.

To reduce the risk of the unit overheating, do the following:

  1. Install an awning over the air conditioner to shade the unit from direct sunlight and weather conditions.

  2. Clean the condenser coils regularly to maintain proper airflow.

  3. Instead of shutting the air conditioner completely off when away from the home, raise the temperature to a higher setting. This will allow the air conditioner to maintain better cooling and humidity control, while reducing the strain on the unit when the temperature is turned back down for more cooling.

E2 or CH01 Error Code

The E2 or CH01 error code is an AUTO-STOP PROTECTION error resulting from a short or open circuit in the indoor pipe sensor. The unit will require a repair service. Please visit our Request a Repair page.

E1 or CH02 Error Code

The E1 or CH02 error code is an AUTO-STOP PROTECTION error resulting from a short or open circuit in the indoor pipe sensor. The unit will require a repair service. Please visit our Request a Repair page.

E3 or CH03 Error Code

The E3 or CH03 error code displays when the unit has detected that there is no refrigerant. The unit will require a repair service, please visit our Request a Repair page.

E4 Error Code

The E4 display is not actually an error code, but indicates that the air conditioner has entered defrost mode. This occurs when the unit detects ice on the evaporator which located behind the front grille. Once defrosted, the air conditioner will resume normal operation.

E5 - Error Code

E5 Error code indicates that the water collection tank is full. To drain the water collection tank completely, leave the bottom drain cap off long enough to allow any residual water to drain out. Once the water tank is completely drained and no more water flows out, reinstall the cap.

EA Error Code

The EA error code indicates that the unit has detected a software issue. The unit will require a repair service. Please visit our Request a Repair page.

P2 or FL Error Code

The P2 or FL error code (depending on model) indicates that the drain pan in the unit is full.

Under normal operating conditions, the drain pan will not need to be emptied. The unit is designed with a slinger fan that is mounted above the drain pan. This fan picks up the water and slings it on to the condenser to help discharge heat. There is usually not enough water in the drain pan to cause the air conditioner to shut off.

Select the condition from the list below in which the P2 or FL error code displays:

  • If the P2 or FL error code is displaying on the air conditioner, remove the drain port cap and tilt the air conditioner to the back so the water runs out of the drain outlet.

    Drain Port 1

    If the unit is in COOL mode and the P2 or FL error code keeps coming back, this indicates that the room is very humid and the unit is working well.

    To drain the unit less frequently, turn the fan speed to LOW. This will slow the air circulation in the room and, thus, the amount of moisture the unit removes. Also, make sure all doors and windows are shut in order to create a controlled environment.

    If the unit is in DRY mode, the unit is running primarily to remove moisture from the air. Change to the setting to COOL mode to reduce the amount of moisture being removed from the room. Some models may allow a hose to be connected for continuous drain. Refer to the model-specific owner's manual for details.

  • If the P2 or FL error code is displaying on the air conditioner, remove the drain port cap and tilt the air conditioner to the back so the water runs out of the drain outlet.

    Drain Port 2

    If no water is draining out when the air conditioner is tilted to the back, the unit will require a repair service. Please visit our Request a Repair page.

  • If after tilting the unit to the back to drain the P2 or FL error code remains, perform a reset on the air conditioner.

    To perform a reset:

    1. Unplug the air conditioner, leaving it unplugged for at least 10 seconds.

    2. Plug the air conditioner back in.

    3. Press the POWER button to turn the air conditioner back on.

    If the P2 or FL error code appears after performing a reset. The unit will require a repair service. Please visit our Request a Repair page.

  • If the P2 or FL error code appears on the air conditioner's display but the unit continues to run. The unit will require a repair service, please visit our Request a Repair page.

F1, F2, F3 Error Code

The unit is in FAN mode and the number shown is the set fan speed. This is a normal operation. The air conditioner is working properly.

Author - Sanmi Ajanaku

Sanmi is a Home Appliance expert and author of this help library article. Please leave him feedback below about the page.

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