Abstract: A heat exchanger manifold (44) is provided which includes a plurality of manifold inlet openings (58) including sealant means such as grommet means (62) which receive the tube outlets (40c) of the condensing section (34) of a heat exchanger (28). The heat exchanger manifold (44) is made of a corrosion-resistant material such as a polymer such as one sold under the trademark LEXAN.TM. and the grommets (62) are preferably made of a resilient, corrosionresistant polymer such as rubber, e.g., a nitrile rubber. The condensing tubes (38a, 38b, 38c) are slanted to facilitate drainage of the condensate into the heat exchanger manifold (44) and a flue gas outlet (64) and a condensate drain (49) are provided to discharge, respectively, flue gas and condensate from the heat exchanger manifold (44). The condensing tubes (38a, 38b, 38c) are connected to the primary heating section (30) of the heat exchanger (28) through swaged joints (37).

Abstract: A single forced air furnace (10) may be installed in any of an upflow, downflow, or horizontal airflow orientation, with discharge of flue gases either opposite to or concurrent with the primary airflow path. The combination of design features which provides this versatility includes the following features: an inducer assembly (24) for withdrawing flue gas from the furnace heat exchanger (20), which inducer assembly (24) may be positioned to direct the discharge of flue gas in a selected one of a plurality of directions; an optional internal flue duct (64) for directing the flue gas through the furnace vestibule chamber then through the furnace housing (12); and the fact that the furnace housing (12) is dimensioned and configured so that the furnace may be supported on any one of four different sides (O, I, S.sub.1, S.sub.2) of the furnace housing (12).

Abstract: A forced air furnace (11) has a heat exchanger (35) with one or more tube pack assemblies (10). Each tube pack assembly (10) has a burner (21) situated to fire into a primary fire tube (30) which is mechanically connected through a transition cap (36) to a plurality of secondary tubes (37, 38, 39, 41) returning combustion products from the primary fire tube (30) to a collection manifold (24) at the intake end of a draft inducer assembly (23) for discharge of the combustion products to a flue. In the preferred embodiment, the transition cap (36) is connected to the primary fire tube (30) and to the secondary tubes (37, 38, 39, 41) by a mechanical interlock.

Abstract: This invention relates to a method and apparatus for shutting down a combustion system when a pressure greater than atmospheric pressure is present in the flue pipe of the system. The apparatus comprises a connector means for connecting the flue pipe of the system with the surrounding atmosphere and a thermal switch which is in thermal contact with and responds to the gases within the connector means. The apparatus is especially useful as a safety device for shutting down an induced draft combustion system when the flue pipe of the system is blocked. Also, the apparatus can be used with a combustion system having a flue outlet vent which is also used as the outlet vent for another combustion system.