| 摘要 |
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. The primary heat exchanger assembly may include a plurality of aligned tubes wherein each tube includes a first straight portion, an intermediate portion, and a second straight portion such that the primary heat exchanger tubes surround the secondary and the tertiary heat exchanger assemblies such that the airflow is configured to traverse the primary heat exchanger assembly, the secondary heat exchanger assembly, and the tertiary heat exchanger assembly in various directions such that a risk of condensation freezing within the secondary and tertiary heat exchange assemblies is reduced. |
