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Power Issues - Room Air Conditioner

Troubleshooting Air Conditioners Last Updated 08/30/2018
Power Issues - Room Air Conditioner

If the air conditioner does not power on, possible causes are; power outage in the home tripped the circuit breaker, the outlet that the unit is plugged into does not have power, or the unit may require a repair service.

  1. Select the type of air conditioner you have:

  2. Note: If you are having issues with a split unit or duct free air conditioner, they are considered business units and will not be covered in this article, please visit www.lg-dfs.com for further support.

Unit won't power ON.

If the air conditioner does not power on, possible causes are: power outage in the home tripped the circuit breaker, the individual outlet has no power, or the unit is defective.

  1. Power Indicator

    The air conditioner power plug has an indicator light which can be OFF (No Light), GREEN, or RED (orange).

    • Plug the air conditioner into the wall outlet.

    What is the STATUS (color) of the power plug INDICATOR LIGHT?

    OFFGREENRED

Unit powers ON, but won't run.

  1. Dedicated Circuit

    How to check - Method 1

    If you know what breaker the unit is powered from, you can trip the breaker at the breaker box. If other devices are WITHOUT power besides the air conditioner, then the unit is not on a dedicated circuit breaker.

    How to check - Method 2

    Turn off all other electrical devices in the room besides the air conditioner. If the unit runs fine with other devices turned off, then likely the unit is not on a dedicated circuit breaker.***

    Is the unit powered on a dedicated circuit breaker?

    YesNo

Portable air condition must be plugged into a grounded 60Hz, 120VAC, outlet protected by a 15amp time delay fuse or circuit breaker.

The outlet must be rated to provide the proper power level to the unit. If you only changed the outlet to match the power cord plug, but did not have the outlet rewired, then the unit will not be receiving the correct power.

Proceed to Mode Setting
  1. Current Mode

    Let's check the control panel to verify that the unit is on the right setting.

    What mode is the unit currently running?

    COOL and TEMP setting set lower than ambient temperatureNot set to COOL mode

  1. Is the unit completely unresponsive even with correct outlet and power supply?

    Completely UnresponsiveFan runs, but the unit is not cooling?

Unit powers ON, but won't run.

  1. Dedicated Circuit

    Test Method 1

    If you know what breaker the unit is powered from. You can trip the breaker at the breaker box. If other devices are WITHOUT power, then the unit is NOT on a dedicated circuit breaker.

    Test Method 2

    Turn off all other electrical devices in the room besides the air conditioner. If the unit runs fine with other devices turned off, then likely the unit is not on a dedicated circuit breaker.***

    Is the unit powered on a dedicated circuit breaker?

    YesNo

Check for adequate power supply.

Check the specifications for your model to determine the power requirements. Your model's power specification is described in the owner's manual. Visit our Manuals and Documents page to download your copy.

Unit requires a 208/230 volt.

The outlet must be rated to provide the proper power level to the unit. If you only changed the outlet to match the power cord plug, but did not have the outlet rewired, then the unit will not be receiving the correct power.

Unit uses a 115 volt.

If the outlet is receiving the correct power supply and is on a dedicated circuit, then we need to check the Mode settings following the link below.

Proceed to Mode Setting
  1. Current Mode

    Let's check the control panel to verify the unit is on the right setting.

    What mode is the unit currently running?

    COOL and TEMP setting set lower than ambient temperatureNot set to COOL mode
  1. Is the unit completely unresponsive even with correct outlet and power supply?

    Completely UnresponsiveFan runs, but the unit is not cooling?

Powers OFF and ON intermittently.

Air conditioners manufactured after 2010 contain a SAFETY RELAY, which automatically powers the unit OFF if the condenser overheats. After the unit cools down, the safety relay resets and normal operation should resume.

When the safety relay is active; the following scenario will be noticed:

Through the Wall and Window Units

The unit will shut off totally. The display, fan, and compressor will shut off.

Portable Units

The unit will shut down partially. The display and compressor will shut off, but the fan will continue to run.

If the safety relay frequently shuts the air conditioner off, check the following installation issues:

  1. Install the unit under shade.

    If the air conditioner is installed in direct sunlight, the air temperature around the air conditioner can cause the unit to overheat. Installing in a shaded area can resolve this issue.

    We recommend installing an awning or shade cover over the air conditioner to resolve the issue.

  2. Clear obstructions.

    Obstructions around the unit can block the airflow, causing the unit to overheat. Refer to the owner’s manual for proper clearance requirements.

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

    distance from wall
  3. Clean the filter.

    Accumulation of dust and other debris on the filter and condenser can restrict airflow causing the unit to overheat.

    Regular maintenance on the air filter is recommended to prevent air flow from being blocked so the unit runs at peak efficiency. Please refer to our Regular Maintenance - Room Air Conditioner article for more information.

    clean filter

Powers OFF and ON intermittently.

Air conditioners manufactured after 2010 contain a SAFETY RELAY, which automatically powers the unit OFF if the condenser overheats. After the unit cools down, the safety relay resets and normal operation should resume.

When the safety relay is active; the following scenario will be noticed:

Through the Wall and Window Units

The unit will shut off totally. The display, fan, and compressor will shut off.

Portable Units

The unit will shut down partially. The display and compressor will shut off, but the fan will continue to run.

If the safety relay frequently shuts the air conditioner off, check the following installation issues:

  1. Install the unit under shade.

    If the air conditioner is installed in direct sunlight, the air temperature around the air conditioner can cause the unit to overheat. Installing in a shaded area can resolve this issue.

    We recommend installing an awning or shade cover over the air conditioner to resolve the issue.

    install a awning or shade
  2. Clear obstructions.

    Obstructions around the unit can block the airflow, causing the unit to overheat. Refer to the owner’s manual for proper clearance requirements.

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

    remove obsstructions
  3. Clean the filter.

    Accumulation of dust and other debris on the filter and condenser can restrict airflow causing the unit to overheat.

    Regular maintenance on the air filter is recommended to prevent air flow from being blocked so the unit runs at peak efficiency. Please refer to our Regular Maintenance - Room Air Conditioner article for more information.

    clean filter

Trips circuit breaker OFF.

  1. Power recommendation.

    Portable air condition must be plugged into a grounded 60Hz, 120VAC, outlet protected by a 15amp time delay fuse or circuit breaker.

  2. Install unit on dedicated circuit.

    If the outlet has the correct voltage, but the breaker is tripping and causing the loss of power, we can preform a simple test to see if other devices are powered on the same circuit as your air conditioner.

    • Turn off all other electrical devices in the room besides the air conditioner.

    • If the unit runs fine with other devices turned off, then likely the unit is not on a dedicated circuit breaker.

    • If the unit is NOT on a dedicated circuit breaker, the unit may power on but not run.

      The reason for this is the unit does not require as much power to display the settings, or even run the fan, as it does to turn on and run the compressor. The A/C must be on a dedicated circuit breaker and not share with other outlets.

Trips circuit breaker off.

  1. Power recommendation.

    Check if the unit have an adequate power supply, the two scenarios below are the most common.

    Unit requires a 208/230 volt.

    The outlet must be rated to provide the proper power level to the unit. If you only changed the outlet to match the power cord plug, but did not have the outlet rewired, then the unit will not be receiving the correct power.

    Unit uses a 115 volt.

    The outlet has the correct voltage, but the breaker is tripping and causing the loss of power. We can to perform a simple test to see if other devices are powered on the same circuit as your air conditioner.

    NOTE: Check the specifications for your model to determine the power requirements. Your model's power specification is described in the owner's manual. Visit our Manuals and Documents page to download your copy.

  2. Install unit on dedicated circuit.

    AC units are built to operate on a dedicated circuit. Test the unit with other appliances in the room to know if its running on a dedicated circuit.

    • Turn off all other electrical devices in the room besides the air conditioner.

    • If the unit runs fine with other devices turned off, then likely the unit is not on a dedicated circuit breaker.

    • If the unit is NOT on a dedicated circuit breaker, the unit may power on but not run.

      The reason for this is the unit does not require as much power to display the settings, or even run the fan, as it does to turn on and run the compressor. The A/C must be on a dedicated circuit breaker and not share with other outlets.

Turns OFF abnormally.

  1. Are there any items nearby to the AC unit that are obstructing air flow?

    YesNo
    obstructed portable unit
  1. Does the unit completely lose power (completely unresponsive to controls) or just stop running?

    Completely Loses PowerJust Stops Running
  1. Does the breaker trip off when the unit loses power?

    Yes, breaker tripsNo, Check AFCI
  1. Was the power lost because the AFCI (arc fault circuit interrupter) tripped on the power cord?

    Yes, AFCI is TrippedNo, AFCI hasn't Tripped afci power cord

Turns OFF abnormally.

  1. Are there any items nearby to the AC unit that are obstructing air flow?

    YesNo
    obstructed portable unit
  1. Does the unit completely lose power (completely unresponsive to controls) or just stop running?

    Completely Loses PowerJust Stops Running
  1. Does the breaker trip off when the unit loses power?

    Yes, breaker tripsNo, Check AFCI
  1. Was the power lost because the AFCI (arc fault circuit interrupter) tripped on the power cord?

    Yes, AFCI is TrippedNo, AFCI hasn't Tripped afci power cord

Turns ON every couple of minutes.

The unit will turn off and on every couple of minutes if it is running on ENERGY SAVER MODE, or the unit is installed in a room smaller to the capacity size of the unit.

  1. Energy Saver is Active

    Energy saver mode will allow the unit to run until the desired room temperature is reached. Once that has been met, the unit will TURN OFF both the compressor and circulation fan.

    After that the circulation fan will cycle on approximately every 3 minutes to test the room air to determine if active cooling needs to resume.

    If this is too disruptive, you may consider swapping the unit to COOL mode. If this is mainly an issue during night time hours, you may want to consider setting an OFF timer to shut the unit down after you’ve fallen asleep and the outside temperature has cooled down for the night.

  2. Unit's size compared to room size.

    An air conditioner that has a BTU ratting for a large room will not work efficiently in a space that is too small. If a large capacity unit is placed in a room that is too small, cool air blowing out of the vents will lower the temperature of the room too rapidly causing the unit to stop active cooling. This leads to the unit cycling on and off very frequently because the unit is overpowered relative to the size of the room it’s in.

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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