Check the dehumidifier power cord. If the power cord is not plugged into an electrical outlet, plug it into the nearest appropriate outlet. Make sure the plug is securely seated in the outlet.
Check the humidity control setting. Turn the humidity setting control knob to a drier setting. The air may not be humid enough for the unit to come on.
Check the drain tank. If the drain tank is full, the dehumidifier will not run. Remove the drain tank by sliding it toward you, and then empty the tank.
Check the coils for frost. If the air temperature is too cold, the coils may frost over and cause the unit to stop working properly. Adjust the air temperature or move the dehumidifier to a warmer area of the room.
Clean the air filter. Remove the air filter cover on the dehumidifier, using your fingers. Remove the air filter by gently lifting it out of the holder. Clean the air filter with a damp cloth. Reinstall the air filter and cover.