Abstract: An indirect gas-fired condensing furnace assembly and method includes a primary heat exchanger, a secondary heat exchanger, and a tertiary heat exchanger. The secondary heat exchanger assembly may be an intermediate single-pass tubular heat exchange section made from a corrosion-resistant material. The tertiary heat exchanger assembly may be a single-pass tubular heat exchanger section with a corrosion resistant material. The tertiary heat exchanger assembly may include a plurality of fins.

Abstract: The present provides a condensing heat exchanger assembly that includes a plurality of heat exchanger passes. The condensing furnace includes a burner assembly having a combustion air device and further includes a frame having primary heat exchanger with a first pass and a second pass. A secondary heat exchanger having a third pass and a fourth pass. The primary heat exchanger assembly may be generally parallel to the secondary heat exchanger assembly such that supply airflow may traverse over the primary and secondary heat exchangers simultaneously in both a first direction and in an opposite second direction. The first pass may include a single drum. The second pass, third pass and fourth pass may include a plurality of aligned tubes.

Abstract: An indirect gas-fired condensing furnace assembly and method includes a primary heat exchanger, a secondary heat exchanger, and a tertiary heat exchanger. The secondary heat exchanger assembly may be an intermediate single-pass tubular heat exchange section made from a corrosion-resistant material. The tertiary heat exchanger assembly may be a single-pass tubular heat exchanger section with a corrosion resistant material. The tertiary heat exchanger assembly may include a plurality of fins.

Abstract: A condensing furnace assembly and method includes a primary heat exchanger having a first zone and a second zone, and a secondary heat exchanger having a first zone and a second zone. A manifold assembly includes a first set and a second set of burners. The primary and secondary heat exchanger assemblies may include a plurality of aligned tubes. The plurality of tubes may include a first zone and a plurality of the tubes include a second zone. A first air device is in communication with the first zone portions of the primary and secondary heat exchanger and the first set of burners. A second air device is in communication with the second zone of the primary and secondary heat exchangers and the second set of burners. The assembly provides for high efficiency operation (90%+ efficiency) and high turndown operation (10:1 or 10% of a maximum firing rate).

Abstract: The present provides a condensing heat exchanger assembly that includes a plurality of heat exchanger passes. The condensing furnace includes a burner assembly having a combustion air device and further includes a frame having primary heat exchanger with a first pass and a second pass. A secondary heat exchanger having a third pass and a fourth pass. The primary heat exchanger assembly may be generally parallel to the secondary heat exchanger assembly such that supply airflow may traverse over the primary and secondary heat exchangers simultaneously in both a first direction and in an opposite second direction. The first pass may include a single drum. The second pass, third pass and fourth pass may include a plurality of aligned tubes.