A fuel-fired water heater has a three-pass condensing type heat exchanger disposed within its tank and having a central vertical first pass flue pipe separated into upper and lower portions by an internal dividing structure. The selection of a medium is performed in a way that prevents the number of writeable media from exceeding the number of available drives, unless no allocated medium has sufficient space to store any files in a migration job. A first air ejection system is configured to generate a first airstream that ejects the identified objects from the trajectory path into a second near receiving bin.