A multi-position furnace is provided that can be positioned for downflow operation, upflow operation, left horizontal flow operation, or right horizontal flow operation without major modifications in the field. The furnace includes a multi-position condensate draining system which facilitates draining of condensate fluid regardless of the orientation of the furnace. The condensate draining system includes a header box and an exhaust manifold, each of which includes a number of drain ports that allow fluid condensing from combustion gasses to be drained regardless of furnace orientation. A trap is configured for attachment to the furnace in any one of four different positions, and receives condensate fluid from the header box and from the exhaust manifold. An air intake manifold is specially configured to maintain a low profile, thereby facilitating use of the multi-position condensate draining system.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a multi-position furnace, and in particular, to a furnace capable of operating in upflow, downflow, and horizontal positions.

2. Background Art

Installation of furnaces can be a time consuming and costly process, particularly when space is limited. Because of space limitations, an installation technician may need to orient a furnace one particular way in order to install the furnace in the desired location. When a furnace is configured from the factory to be installed in only one or two different orientations, it may not be able to fit into the desired location. When this occurs, one of a number of events must take place: the furnace must be installed in a different location, a different furnace must be installed, or the existing furnace must be modified in the field to accommodate the desired location. Having an installation technician modify various components of a furnace in the field adds complexity, time and cost to the installation.

Therefore, a need exists for a furnace that can be installed in various vertical and horizontal positions, so as to eliminate the need for extensive modification of furnace components in the field.

SUMMARY OF THE INVENTION

Accordingly, the present invention provides a furnace for supplying heated air to a space to be heated and capable of being installed in more than one position. The furnace includes at least one burner and a heat exchanger in communication with the at least one burner to receive products of combustion therefrom. The furnace further includes an inducer in communication with the heat exchanger for inducing a flow of products of combustion through the heat exchanger and out of the furnace. The furnace comprises a multi-position condensate draining system. The condensate draining system includes a manifold disposed between the heat exchanger and the inducer. The manifold includes at least three drain ports positioned to drain fluid, such that at least one of the drain ports is capable of draining fluid from the manifold when the furnace is positioned for downflow operation, upflow operation, left horizontal flow operation, or right horizontal flow operation.

The invention also provides a furnace for supplying heated air to a space to be heated and capable of being installed in more than one position. The furnace includes at least one burner and a heat exchanger in communication with the at least one burner for receiving products of combustion therefrom. The furnace includes an inducer in communication with the heat exchanger for inducing a flow of products of combustion through the heat exchanger and out of the furnace. The furnace comprises a multi-position condensate draining system. The condensate draining system includes an exhaust manifold in communication with the inducer and an ambient environment. The exhaust manifold is configured to facilitate transfer of combustion gases out of the furnace. The exhaust manifold includes at least three drain ports positioned to drain fluid from the exhaust manifold. At least one of the drain ports is capable of draining fluid when the furnace is positioned for downflow operation, upflow operation, left horizontal flow operation, or right horizontal flow operation.

The invention further provides a furnace for supplying heated air to a space to be heated and capable of being installed in more than one position. The furnace includes a cabinet generally defining a furnace interior, at least one burner, and a heat exchanger. The heat exchanger is in communication with the at least one burner, and receives products of combustion therefrom. The furnace further includes an inducer in communication with the heat exchanger for inducing a flow of products of combustion through the heat exchanger and out of the furnace. The furnace also includes a plurality of manifolds, each of which is configured to receive products of combustion and to facilitate transfer of combustion products out of the manifold. The furnace comprises a multi-position condensate draining system. The condensate draining system includes at least three connectors attached to the cabinet. Each of the connectors includes at least one inlet cooperating with a corresponding cabinet wall to facilitate fluid flow through the corresponding cabinet wall. The connectors are positioned on the cabinet such that at least one of the connectors is capable of receiving fluid through a corresponding connector inlet when the furnace is positioned for downflow operation, upflow operation, left horizontal flow operation, or right horizontal flow operation. The condensate draining system further includes a trap having at least one inlet cooperating with one of the connectors to receive fluid from a corresponding connector inlet. The trap is in communication with an ambient environment, and is configured to inhibit non-liquid products from passing through the trap and into the ambient environment.

The invention also provides a furnace for supplying heated air to a space to be heated and capable of being installed in more than one position. The furnace includes an air intake for receiving air from an ambient environment, at least one burner, and a heat exchanger in communication with the at least one burner to receive products of combustion therefrom. The furnace further includes an inducer in communication with the heat exchanger for inducing a flow of products of combustion through the heat exchanger and out of the furnace. The furnace comprises an air intake manifold disposed between the furnace air intake and the heat exchanger, and configured to facilitate airflow therebetween. The air intake manifold includes an outlet and at least one inlet. The at least one inlet communicates with the furnace air intake, and the outlet communicates with the at least one burner. The at least one inlet includes a first portion with a first cross section having a linear dimension and defining a first area. The at least one inlet also includes a second portion with a quadrilateral cross section having a depth and a height and defining a second area. The depth of the quadrilateral cross section is smaller than the linear dimension of the first cross section.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

FIGS. 1–4show a furnace10in accordance with the present invention. The furnace10is shown inFIG. 1in an upflow position, and inFIGS. 2–4, it is shown in a downflow, right horizontal flow, and left horizontal flow position, respectively. Referring now toFIGS. 1–4, and in particular,FIGS. 1 and 4, the furnace10includes a cabinet12which generally defines a furnace interior14. The furnace interior14is divided into two compartments by an interior partition16. On one side of the partition16is a blower compartment in which a supply air blower18is located. On the other side of the partition16is a heat exchanger compartment, in which a primary heat exchanger20and a secondary heat exchanger22are located. The furnace10also includes a number of burners24, which burn a combustible gas-air mixture. The burners24communicate with the primary heat exchanger20, which in turn, communicates with the secondary heat exchanger22. Hot combustion gasses from the burners24flow through the primary heat exchanger20where they are cooled prior to flowing through the secondary heat exchanger22. A gas valve26controls the supply of gas to the burners24, and an induced draft blower, or inducer28, induces a flow of products of combustion through the heat exchangers20,22.

The furnace10also includes a multi-position condensate draining system, indicated generally by the numeral30, and described in detail with reference to individual elements of the system30. For example, the condensate draining system30includes a manifold, or cold end header box32. As shown inFIG. 4, the header box32is disposed between the inducer28and the secondary heat exchanger22. As best seen inFIG. 5, the header box32includes four drain ports34positioned to drain condensate fluid. The drain ports34are positioned so that at least one of them is capable of draining fluid from the header box32when the furnace10is positioned for downflow, upflow, left horizontal flow, or right horizontal flow operation. An aperture35allows the header box32to communicate with the inducer28.

As shown inFIGS. 6 and 7, the header box32includes a first portion36and a second portion38. The first and second portions cooperate to define first and second chambers40,42. The first portion36includes the drain ports34, which are configured to facilitate fluid flow out of the second chamber42. A sharp edged orifice44is disposed through the second portion38, and allows the inducer28to draw combustion gasses from the second heat exchanger22into the second chamber42. A gasket46surrounds the aperture35to seal the interface between the header box32and the inducer28.

When the furnace10is in operation, the inducer28draws combustion gasses from the secondary heat exchanger22through the header box32, thereby creating a negative pressure in both the first and second chambers40,42. The pressure in the first chamber40is slightly more negative than the pressure in the second chamber42. As condensate collects in the header box32, it tends to collect in the second chamber42. As shown inFIG. 6, the second portion38of the header box32includes four drain holes48. If condensate fluid does collect in the first chamber40, the drain holes48allow the condensate to drain from the first chamber40into the second chamber42when the furnace10is in an off cycle. Because of the placement of the holes48, fluid will drain out of the first chamber40regardless of whether the furnace10is positioned for downflow, upflow, left horizontal flow, or right horizontal flow operation.

As shown inFIG. 6, the first manifold portion36includes four side members50,52,54,56. The second manifold portion38is offset from the side members50,52,54,56by a predetermined distance (d1). Providing this offset helps to ensure that condensate building up in the second chamber42will not flow back into the first chamber40through the drain holes48. Although the second manifold portion38is shown inFIG. 6having an offset distance (d1) that is the same on all four sides of the first manifold portion36, one or more of the sides may have a different offset distance, as desired.

As best seen inFIG. 5, the header box32includes two pairs of bosses58,60and62,64, each of which is disposed in the first manifold portion36. A first boss58,62in each of the pairs, is in communication with the first chamber40. Conversely, the second boss60,64in each pair, is in communication with the second chamber42. As shown inFIG. 5, the second bosses60,64are indicated by a plus sign (+). As discussed above, when the inducer28is operating, the pressure in the second chamber42is not positive, but it is slightly less negative than the pressure in the first chamber40. Hence, the plus sign (+), which may be conveniently used to distinguish the bosses, is indicative of a relative pressure between the two chambers40,42. By having one boss58,62from each pair communicate with the first chamber40, and a second boss60,64from each pair communicate with the second chamber42, it is easy to obtain a pressure differential across the orifice44.

FIG. 1shows two pressure sensors66,68, one of which, the pressure sensor66, is connected to one of the pairs of bosses58,60with hoses (not visible). The second pressure sensor68is attached to the other pair of bosses62,64. By providing the furnace10with two factory installed pressure sensors66,68, each of which is already attached to a corresponding pair of bosses, an installation technician does not need to install a pressure sensor in the field, regardless of the furnace orientation. The bosses58,62, are located far enough away from the edges of the second portion38that it is not likely that condensate will accumulate enough to fill either of them. If, however, condensate does accumulate enough to plug one of the bosses58,62, it may be indicative of a condensate draining problem. To address this issue, the pressure sensors66,68can be configured to disable the furnace if the differential pressure being measured is less than a predetermined pressure, which may occur if one of the bosses becomes blocked with liquid condensate.

FIGS. 8–11show different styles of connectors that can be used with the furnace10. In order to facilitate ease of installation of the furnace10in any of the four flow positions discussed above, two connectors72, and two other connectors74, are attached to cabinet walls76,78. Each of the connectors72,74is connected by a hose80(only three of which are visible inFIG. 1) to a respective drain port34in the header box32. A trap82is connected to one of the connectors, such as the connector72shown inFIG. 1, to receive the condensate fluid from the header box32. The furnace10can be assembled at the factory with all of the connectors72,74installed in cabinet walls, and with a hose attached to a respective drain port34in the header box32. Thus, the furnace10can be installed for downflow, upflow, left horizontal flow, or right horizontal flow operation, and the installation technician need only attach the trap82to the appropriate connector to facilitate proper condensate draining.

FIGS. 8 and 9show the connectors72. Each connector72has two inlets84,86, only one of which will receive a hose80from a drain port34on the header box32. As explained more fully below, the other inlet in each of the connectors receives condensate from a different portion of the condensate draining system30. The inlets84,86are configured with straight connectors, and are therefore used where there is ample room for a hose to approach the connector72straight-on. The connectors72may be made from acrylonitrile butadiene styrene (ABS), or some other suitable material. Bosses88can be molded into the connector72to facilitate attachment of the connector72to a corresponding furnace wall with a threaded fastener or the like. Unlike the straight connectors72, the connectors74, shown inFIGS. 10 and 11, have inlets90,92that are offset 90° to facilitate attachment of hoses in areas of the furnace10where there may not be room enough for a hose connection to a straight connector, such as the connectors72. As with the connectors72, the connectors74include bosses94which facilitate connection of the connectors74to a corresponding cabinet wall.

As discussed above, each of the connectors72,74includes two inlets, only one of which is connected to the header box32. The other inlet on each connector72,74is connected to an exhaust manifold96. The exhaust manifold96is in communication with the inducer28and ambient environment, usually outside the building being heated. The exhaust manifold96receives combustion gasses from the inducer28, and transfers them outside of the furnace10, usually through an exhaust duct (not shown) which is open to the ambient environment outside the building. As shown inFIG. 12, the exhaust manifold96includes an inlet98, and two outlets100,102. The inlet98receives the combustion gasses from the inducer28, while one of the outlets100,102is connected to an exhaust duct to vent the combustion gasses outside the building. The other outlet100,102can be capped-off at the time the furnace10is installed. The exhaust manifold96includes four drain ports104,106. By having four drain ports, the exhaust manifold96can be installed in the furnace10at the factory, and no adjustments are needed in order for condensate to effectively drain when the furnace is positioned for downflow, upflow, left horizontal flow, or right horizontal flow operation. Thus, an installation technician need only cap one of the outlets100,102depending on the installation orientation of the furnace10. Each of the drain ports104,106is attached to a corresponding connector72,74with a hose108, only one of which is visible inFIG. 1.

The exhaust manifold96, which can be made from ABS, or any other suitable material, is conveniently configured in three pieces. As shown inFIG. 12, the exhaust manifold96includes a tee110and two pipe sections112,114. Each of the pipe sections112,114may be conveniently attached to the tee110with clamps116. The two pipe sections112,114are substantially the same, except for the length. This makes the exhaust manifold96a versatile component, in that merely changing the length of one of the two pipe sections changes the offset of the inlet98to accommodate various furnace configurations.

FIG. 13shows a cross section of the pipe section114. The pipe section114includes a flange118that includes a pair of mounting holes120that are used to connect the pipe section114to the cabinet12. An exhaust vent121, shown in phantom inFIG. 1, can be glued to the outlet102and vented to an ambient environment. The side of the exhaust manifold96opposite the exhaust vent121will be capped. From the cross section shown inFIG. 13, it is clear that the drain port106has a larger diameter than the drain port104. The drain port106has a larger diameter to help ensure that condensate does not flow out of the inlet98and back into the inducer28when the furnace10is oriented for upflow operation. As shown inFIG. 1, when the furnace10is oriented for upflow operation, the exhaust manifold96is above the inducer28. In this orientation, condensate forming in the exhaust vent121can flow back into the exhaust manifold96and into the inducer28. Therefore, the larger drain ports106help to ensure that all of the condensate received by the exhaust manifold96is successfully drained into the trap82. When the furnace10is configured for downflow operation or horizontal operation, the exhaust manifold96is not located above the inducer28, and the drain ports104, are large enough to drain all of the condensate that accumulates in the exhaust manifold96.

FIG. 14shows a perspective view of the trap82. The trap82includes two inlets122,124. The inlets122,124are configured to fit into the connectors72,74on the outside of the cabinet12, as shown inFIG. 1. As described above, one of the connectors72,74receives condensate fluid from the header box32, and the other of the connectors72,74receives condensate fluid from the exhaust manifold96. Thus, one of the inlets122,124of the trap82receives fluid from the header box32, while the other inlet122,124receives fluid from the exhaust manifold96. Because the trap82is substantially symmetrical, either inlet122,124can be configured to communicate with either the header box32or the exhaust manifold96.

The trap82also includes flanges126,128,130. Each of the flanges126,128,130includes a mounting hole132that can be used to attach the trap82to the furnace cabinet12with, for example, threaded fasteners. The trap82also includes drain ports134,136, one of which can be connected to a drain which communicates with the ambient environment outside the furnace10. The other drain port134,136can be capped at the time of installation. To facilitate cleaning of the trap82, clean-out holes137,139are provided—seeFIGS. 14 and 16. The clean-out holes137,139have plugs (not shown) installed at the factory, to keep condensate from draining out of the trap. When a service technician wants to clean a trap, such as the trap82, the plugs are easily removed, and replaced when the cleaning is complete.

FIG. 15shows a cross section of the trap82taken through lines15—15inFIG. 14. The trap82includes a first partition138that divides the inside of the trap82into first and second chambers140,142. As shown inFIG. 16, a second partition144defines a third chamber146within the trap82. Condensate water collecting in the trap82will effectively form a pressure seal that keeps exhaust gasses from the exhaust manifold96from passing through the trap82and into the ambient environment.

In addition to having a condensate draining system30which facilitates easy installation of the furnace10in various different flow orientations, the furnace10also provides installation in a relatively small space because of the compact configuration of various components. For example,FIG. 1shows an air intake manifold148configured to receive air from a furnace air intake150, shown in phantom. The air intake manifold148is disposed between the furnace air intake150and the burners24. As best seen inFIG. 17, the air intake manifold148includes a pair of inlets152,154, and an outlet156. At the time the furnace10is installed, one of the inlets152,154can be connected to an air intake, such as the air intake150. The other inlet152,154can be capped by the installation technician.

The air-intake manifold148includes three separate pieces, the two inlets152,154and a channel158. The inlets152,154are configured substantially the same, and can be attached to either side of the channel158.FIGS. 18 and 19show one of the inlets152in detail; however, it is understood that the following description applies equally to the inlet154. As shown inFIG. 18, the inlet152includes a first portion160, a second portion162, and a transition portion164between the first and second portions160,162. In the embodiment shown inFIGS. 17–19, the first portion160of the inlet152has a round cross section with an inside diameter (D) that defines a first area. The round cross section of the first portion160facilitates attachment of an air intake, such as the air intake150, which may commonly be one or more sections of polyvinyl chloride (PVC) or ABS pipe.

As best shown inFIG. 19, the second portion162of the inlet152has a generally rectangular cross section, defined by a depth (d2) and a height (h), which define a second area. The depth (d2) of the second portion162is smaller than the inside diameter (D) of the first portion160. This gives the air intake manifold148a low profile, which allows it to be installed in a multi-position furnace, such as the furnace10. Moreover, the compact design of the air intake manifold148improves access for servicing and installing other furnace components, and provides clearance for routing the air intake150, a vent pipe, gas supply lines, and condensate drain lines.

In order to ensure that there is not a large pressure drop across the inlet152, the height (h) of the second portion162is larger than the depth (d2). Thus, the second area, which is generally rectangular, and defined by the depth (d2) and the height (h), can be greater than or equal to the first area, which is circular and defined by the inside diameter (D). The transition portion164helps to inhibit airflow resistance as the cross section changes from a circular cross section in the first portion160to the rectangular cross section of the second portion162.

FIG. 20shows the channel158, which includes three sides166,168,170, and two open ends172,174. Each of the inlets152,154includes a plurality of protrusions176—seeFIGS. 17–18. The protrusions176are configured for snap-fit attachment to the channel158at apertures178. As shown inFIG. 17, two protrusions176on each inlet152,154are not attached to the channel158. These protrusions176can be used to locate the air intake manifold148on a burner enclosure180—seeFIG. 1. The air intake manifold148can then be secured to the burner enclosure180with threaded fasteners or the like, inserted through apertures182in flanges184disposed along a length of the channel158.