Abstract:
A method and apparatus for conveying condensate from an exhaust system of a gas water heater to a drain. The method includes the steps of operating the gas water heater to produce products of combustion, operating a blower to cause the products of combustion to flow through the exhaust system to atmosphere, allowing condensate from the products of combustion to form within the exhaust system, using a drain conduit to connect a relatively high pressure zone of the exhaust system to a relatively low pressure zone of the exhaust system, using a pressure differential between the relatively high pressure zone and the relatively low pressure zone to convey condensate through the drain conduit from the relatively high pressure zone to the relatively low pressure zone, and conveying condensate from the relatively low pressure zone to the drain.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority to co-pending U.S. Provisional Patent Application No. 61/407,778 filed on Oct. 28, 2010, the entire content of which is incorporated herein by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    The present invention relates to gas water heaters, and more particularly to gas water heaters including exhaust systems. 
       SUMMARY OF THE INVENTION 
       [0003]    The present invention provides, in one aspect, a method of conveying condensate from an exhaust system of a gas water heater to a drain. The method includes the steps of operating the gas water heater to produce products of combustion, connecting an exhaust outlet of the gas water heater to the exhaust system such that the exhaust system receives the products of combustion, operating a blower to cause the products of combustion to flow through the exhaust system to atmosphere, allowing condensate from the products of combustion to form within the exhaust system, using a drain conduit to connect a relatively high pressure zone of the exhaust system to a relatively low pressure zone of the exhaust system, the relatively low pressure zone between the exhaust outlet and the blower and the relatively high pressure zone downstream of the relatively low pressure zone, using a pressure differential between the relatively high pressure zone and the relatively low pressure zone to convey condensate through the drain conduit from the relatively high pressure zone to the relatively low pressure zone, and conveying condensate from the relatively low pressure zone to the drain. 
         [0004]    The present invention provides, in another aspect, a gas water heater including a storage tank for storing water, a combustion chamber, a burner positioned in the combustion chamber, the burner for producing products of combustion, a heat exchanger positioned in the storage tank for receiving the products of combustion from the combustion chamber and for transferring heat from the products of combustion to the water stored in the storage tank, the heat exchanger including an outlet that extends from the storage tank, and an exhaust system. The exhaust system includes a first exhaust conduit connected to the outlet to receive the products of combustion from the heat exchanger, a second exhaust conduit fluidly connected to atmosphere, a blower connected between the first exhaust conduit and the second exhaust conduit with the first exhaust conduit upstream of the blower and the second exhaust conduit downstream of the blower, a first drain fitting in the first exhaust conduit between the outlet and the blower and a second drain fitting downstream of the first drain fitting such that the first drain fitting is at a first pressure and the second drain fitting is at second pressure, the second pressure greater than the first pressure, and a drain conduit connected between the first drain fitting and the second drain fitting such that the difference between the second pressure and the first pressure causes condensate from the products of combustion to flow through the drain conduit from the second drain fitting to the first drain fitting. 
         [0005]    Other features and aspects of the invention will become apparent by consideration of the following detailed description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0006]      FIG. 1  is a perspective view of a gas water heater. 
           [0007]      FIG. 2  is a perspective view of the gas water heater of  FIG. 1  including a gravity-based condensate drainage system. 
           [0008]      FIG. 3  is a schematic view of the gas water heater of  FIG. 1  including a gravity-based condensate drainage system 
           [0009]      FIG. 4  is a perspective view of the gas water heater of  FIG. 1  including a pressure-based condensate drainage system. 
           [0010]      FIG. 5  is a schematic view of the gas water heater of  FIG. 1  including a pressure-based condensate drainage system. 
       
    
    
       [0011]    Before any embodiments of the invention are explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or of being carried out in various ways. Also, it is to be understood that the phraseology and terminology used herein is for the purpose of description and should not be regarded as limiting. 
       DETAILED DESCRIPTION 
       [0012]      FIG. 1  illustrates a gas water heater  100  including a storage tank  105 , an outer case  110 , a cold water inlet  115 , a hot water outlet  120 , a combustion chamber  125 , a burner  130 , and a flue or heat exchanger  135 . The water heater  100  may also include additional conventional components of a gas-fired storage water heater, for example, a gas valve, a temperature and pressure (T&amp;P) valve, a sacrificial anode, and a drain valve. The storage tank  105  is surrounded by the outer case  110 . The cold water inlet  115  delivers cold water to the storage tank  105  and the hot water outlet  120  delivers hot water to an end-use location, for example, a faucet. The burner  130  is positioned in the combustion chamber  125  and combusts a fuel/air mixture to create products of combustion. The products of combustion flow from the combustion chamber  125  to the heat exchanger  135 . As the products of combustion travel through the heat exchanger  135 , heat is transferred from the products of combustion to the water stored in the storage tank  105 . The heat exchanger  135  includes an outlet  140  that extends from the storage tank  105  through the outer case  110 . 
         [0013]      FIGS. 2-3  illustrate an exhaust system  145  that conveys the products of combustion from the outlet  140  of the heat exchanger  135  to atmosphere. The exhaust system  145  includes a blower  150 , an exhaust conduit  155  upstream of the blower  150 , and an exhaust conduit  160  downstream of the blower  150 . A vent attenuation assembly  165  in the exhaust conduit  160  is optional. The exhaust conduit  155  connects the outlet  140  to the blower  150 . The exhaust conduit  155  extends vertically along the side of the water heater  100  and is spaced apart from the storage tank  105  and the outer case  100 . The exhaust conduit  160  connects the blower  150  to an exhaust vent (not shown). The vent attenuation assembly  165  is positioned between the blower  150  and the exhaust vent to reduce fan noise created by the blower  150 . When the water heater  100  and the blower  150  are operating, the products of combustion travel from the outlet  140  through the exhaust conduit  155 , through the blower  150 , and through the exhaust conduit  160  and vent attenuation assembly  165  to the exhaust vent to be vented to the atmosphere outside of the building containing the water heater  100 , as shown by the dashed arrows in  FIG. 3 . 
         [0014]    As the products of combustion cool in the exhaust system  145 , condensate is formed. The condensate must be drained from the exhaust system  145 . A conventional method of draining the condensate is to use gravity to drain condensate from several locations in the exhaust system  145 . The blower  150  includes drain fittings  170  and  175 . The drain fitting  170  is in the housing of the blower  150  and the drain fitting  175  is in the outlet portion of the blower  150 . The vent attenuation assembly  165  includes a drain fitting  180 . A drain hose or conduit  185  is connected to each drain fitting  170 ,  175 , and  180 . The exhaust conduit  155  includes a lower portion with a trap  190 . The trap  190  is u-shaped and is positioned below the outlet  140  of the heat exchanger  135 . A main drain conduit  195  is connected to the trap  190  and runs to a suitable drain  200 . All of the drain conduits  185  are in fluid communication with the main drain conduit  195 . The drain conduits  185  from the drain fittings  170  and  175  are connected to one another by a tee  205  and then to the main drain conduit  195  by an intermediate conduit  208  and another tee  205 . The drain conduit  185  from the drain fitting  180  is connected to the main drain conduit  195  by a tee  205 . Each of the drain conduits  185  includes a trap loop  210  located upstream of any tee  205  connected to that drain conduit  185 . As condensate forms in the exhaust system  145 , the condensate is drawn by gravity towards one of the drain fittings  170 ,  175 , and  180 . From each drain fitting  170 ,  175 , and  180 , the condensate is drawn by gravity through a corresponding drain conduit  185  to the main drain conduit  195  and through the main drain conduit  195  to the drain  200 , as shown by the solid arrows in  FIG. 3 . Alternatively, each of the drain conduits  185  and the main drain conduit  195  are individually routed to the drain  200 . 
         [0015]    The drawbacks of the gravity-based condensate drainage system as shown in  FIGS. 2-3  include installation, appearance, setup, and function. For installation, the installer can be confused about how to connect and route the drain conduits  185 , even when provided with instructions. For appearance, the multiple drain conduits  185  and loops  210  outside of the water heater  100  and exhaust system  145  can look messy. For setup, each individual drain conduit  185  has to be primed and each individual loop  210  must be formed and positioned correctly. For function, gravity does not ensure complete drainage of the condensate from the exhaust system  145 , which causes nuisances in the field. When the blower  150  is operating, the exhaust conduit  155  is at a first pressure P 1 , the housing of the blower  150  including drain fitting  170  is at a second pressure P 2 , the outlet portion of the blower  150  including drain fitting  175  is at a third pressure P 3 , and the vent attenuation assembly  165  including drain fitting  180  is at a fourth pressure P 4 . Pressures P 1 , P 2 , P 3 , and P 4  all are lower than the ambient pressure at the drain  200 , which causes the drain conduits  185  to not drain well because the pressure differentials between the pressures P 1 , P 2 , P 3 , and P 4  and ambient pressure work against the effect of gravity on the condensate in the drain conduits  185 . Furthermore, as shown in  FIG. 3 , any rise  215  in a drain conduit  185  upstream of a loop  210  traps condensate and air upstream of the loop  210 , thereby inhibiting the flow of condensate through the loop  210  and drain conduit  185 . 
         [0016]      FIGS. 4-5  illustrate the gas fueled water heater  100  and an exhaust system  245  similar to the exhaust system  145  shown in  FIGS. 2-3 . The components of the exhaust system  245  similar to those described with respect to exhaust system  145  are numbered with the same reference numeral plus one-hundred. The exhaust system  245  uses a pressure-based condensate drainage system that overcomes the drawbacks of a gravity-based drainage system as shown in  FIGS. 2-3 . 
         [0017]    The exhaust conduit  255  includes an adaptor  320  positioned near the top of the water heater  100 . The adaptor  320  includes multiple drain fittings  325 . At a minimum, the adaptor  320  includes one drain fitting  325 . The adaptor  320  and the drain fittings  325  are located on a vertical portion  327  of the exhaust conduit  255 . The drain fittings  325  are located adjacent to the top of the water heater  100  and the top of the storage tank  110 . The drain fittings  325  can be poka-yoke or error-proofed fittings which require the installer to remove a plug or other component for each fitting before attaching a drain conduit  285 . This prevents a drain fitting  325  from being left open if the installer does not install the same number of drain conduits  285  as the number of drain fittings  325  provided by the adaptor  320 . In the event a drain fitting  325  is left open and the water heater  100  and the blower  250  are operating, the adaptor  320  will be at a negative pressure relative to atmosphere such that products of combustion will not escape through the open drain fitting  325 . Preferably, the drain fittings  325  are barb fittings. 
         [0018]    Drain fittings  270 ,  275 , and  280  are located downstream of the adaptor  320 . More or fewer drain fittings downstream of the adaptor  320  can be included in the exhaust system  245 . For example, as shown in  FIG. 4 , the blower  250  includes a third drain fitting  330 . Drain conduits  285  are connected between the each of the drain fittings  270 ,  275 ,  280 , and  330  and a drain fitting  325  of the adaptor  320 . The adaptor  320  is positioned below all of the downstream drain fittings  270 ,  275 ,  280 , and  330 . 
         [0019]    As shown in  FIG. 5 , when the blower  250  is operating, the exhaust conduit  255  including drain fittings  325  is at a first pressure P 1 , the inlet of blower  250  including drain fitting  270  is at a second pressure P 2 , the outlet of the blower  250  including drain fitting  275  is at a third pressure P 3 , and the vent attenuation assembly  265  including drain fitting  280  is at a fourth pressure P 4 . The blower  250  runs when the water heater  100  is operating to create products of combustion. The blower  250  may also run before and/or after the water heater  100  is operating to produce products of combustion. The second pressure P 2 , the third pressure P 3 , and the fourth pressure P 4  are all greater than the first pressure P 1 . For example, the second pressure P 2  and the first pressure P 1  are both negative relative to atmosphere with the first pressure P 1  being more negative than the second pressure P 2 , so the second pressure P 2  is considered greater than or higher than the first pressure P 1  relative to atmosphere. 
         [0020]    Each of the drain fittings  270 ,  275 ,  280 , and  330  is located in a relatively high pressure zone when compared to a relatively low pressure zone in which the drain fittings  325  are located. The relatively high pressure zones are located downstream of the relatively low pressure zone in which the drain fittings  325  are located. The pressure differentials between the second pressure P 2  and the first pressure P 1 , the third pressure P 3  and the first pressure P 1 , and the fourth pressure P 4  and the first pressure P 1  drive the condensate from the relatively high pressure zones through a corresponding drain conduit  285  to the relatively low pressure zone in the exhaust conduit  255 . Gravity functions as a subsidiary method of drainage through the drain conduits  285  because the drain fittings  325  of the adaptor  320  are positioned lower than all of the drain fittings  270 ,  275 ,  280 , and  330 . 
         [0021]    Gravity causes the condensate to travel downward through the exhaust conduit  255  from the drain fittings  325  to the trap  290 . Condensate collects in the trap  290  until the collected condensate reaches the elevation of the main drainage conduit  295 , which delivers the condensate to the drain  200 . 
         [0022]    The pressure-based condensate drainage system shown in  FIGS. 4-5  improves on the installation, appearance, setup, and function of the gravity-based condensate drainage system shown in  FIGS. 2-3 . The pressure-based condensate drainage system is easier to install, neater looking, and requires less time to set up than the gravity-based condensate drainage system. For example, there is no need to prime the drain conduits  285  of the pressure-based condensate drainage system, only the main drain conduit  295  needs priming. Additionally, the condensate-based drainage system drains condensate more reliably and functions better than the gravity-based condensate drainage system. 
         [0023]    Various features of the invention are set forth in the following claims.