When enabling DRY mode on portable air conditioners a hose is required to allow the water to drain.   The hose is not included with product.   Any standard garden hose will attach to the drain outlet after removing the drain cap on the rear of the unit.  Be sure that the height of the drain and no portion of the hose is higher than the drain outlet or the continuous drainage may not work properly.

During Cool or Eco mode, it is recommended to disable continuous drainage by replacing the drain cap to the drain outlet to reach maximum performance.   The system is self evaporating and when in these modes do not require to be drained.  Under extreme conditions, such as very high humidity, the internal reservoir may fill.  If this does occur the unit will stop running and display P1.  For instructions on how to drain the reservoir see here.