Diagnosis
The flashing power light on the Costway EP24618US is a safety trigger indicating that the compressor has entered a thermal protection shutdown. Unlike a specific error code (like E1 or P1), a flashing power light typically signifies that the unit's internal temperature sensors have detected an overheat condition in the condenser coils or that the compressor is unable to cycle properly due to insufficient airflow. This happens when the heat exchange process is interrupted. If the hot air cannot be expelled through the exhaust hose or if the intake air is restricted, the refrigerant cannot cool down. This causes the compressor to work harder, increasing the internal temperature until the thermal overload switch trips to prevent the motor from burning out. You can confirm this by feeling the air coming out of the exhaust hose; if it feels lukewarm rather than hot, or if the unit shuts down faster when placed in a smaller, enclosed space, it is almost certainly an airflow restriction issue.
How to Fix It
To resolve the overheating cycle and reset the power light, follow these precise steps:
- Power down the unit completely and unplug the power cord from the wall outlet. Do not simply turn it off via the remote.
- Inspect the exhaust hose. Ensure there are no sharp kinks, bends, or crushed sections. The hose should be as short and straight as possible; any excess length creates back-pressure that traps heat inside the chassis.
- Clear a 20-inch perimeter around the rear exhaust port and the side intake vents. Remove curtains, furniture, or wall hangings that may be obstructing the airflow.
- Remove the front plastic grille and slide out the washable air filters. If they are grey or coated in a layer of dust, rinse them under warm water with a mild detergent.
- Pat the filters dry with a towel and let them air dry completely. Never reinstall damp filters, as moisture can freeze on the evaporator coils, triggering a different shutdown sequence.
- Reinstall the filters and the grille, plug the unit back in, and set the mode to 'Cool' at 65°F to test the cycle.
If That Didn't Work
- Deep Clean the Condenser Coils: If the filters were clean but the unit still trips, the internal condenser coils (located behind the rear panel) are likely packed with fine dust. Unplug the unit, remove the rear housing screws, and use a vacuum with a soft brush attachment to gently clear the aluminum fins. Be careful not to bend the fins, as this permanently restricts airflow.
- Check the Drain Pan: While the flashing light is usually thermal, a full internal reservoir can sometimes cause erratic power behavior. Locate the lower drain plug at the back of the unit. Place a shallow pan underneath and remove the plug to ensure all stagnant water is drained. A clogged drain can lead to humidity buildup that affects sensor readings.
- Verify Voltage Stability: These units are sensitive to voltage drops. If you are using an extension cord, remove it and plug the unit directly into a grounded wall outlet. Extension cords often cause the compressor to draw more current than the circuit can provide, leading to overheating of the electrical components and a subsequent safety shutdown.
- Reset the Internal Logic: Perform a hard reset by leaving the unit unplugged for at least 30 minutes. This allows the capacitors to discharge fully and resets the thermal sensor's trip state, clearing the flashing light memory.
Heads Up
- Always clean the filters every two weeks during peak summer use to prevent the compressor from straining.
- Avoid using "slim" or non-insulated exhaust hoses; these leak heat back into the room and force the unit to run longer, increasing the risk of thermal shutdown.
- Ensure the window slider kit is sealed tightly with weather stripping to prevent hot outdoor air from leaking back in, which creates a thermal loop.
- Never operate the unit in a room where the temperature exceeds 95°F without ensuring the exhaust is vented perfectly, as the ambient heat can prevent the condenser from cooling.