Patent Publication Number: US-2013247843-A1

Title: Systems and methods for venting a water heater

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to water heaters, and more particularly, to systems and methods for venting water heaters. 
     BACKGROUND OF THE INVENTION 
     Conventionally, water heaters are employed (e.g., in one or more buildings) to generate and maintain a readily-usable source of hot water for use (e.g., by the building&#39;s occupants). To generate the heat for heating the water, water heaters include a source of fuel, such as oil or natural gas, which is burned in a combustion chamber. This consumption of fuel generates exhaust gas, which must be vented from the water heater. There exists a need for improved systems and methods for venting exhaust gas from water heaters. 
     SUMMARY OF THE INVENTION 
     Aspects of the present invention are directed to systems and methods for venting a water heater. 
     In accordance with one aspect of the present invention, a vented water heating system is disclosed. The vented water heating system comprises a fuel-fired water heater, a blower, a draft hood, and a thermal switch. The water heater has a combustion gas exhaust outlet. The blower is positioned to advance combustion gas exhausted from the combustion gas exhaust outlet of the fuel-fired water heater. The blower has a blower inlet positioned to receive combustion gas and a blower outlet positioned to exhaust combustion gas. The draft hood defines a passageway positioned to receive combustion gas exhausted from the blower outlet. The draft hood at least partially defines a relief opening positioned to allow gas to enter into or exit from the passageway of the draft hood. The thermal switch is positioned to detect a blockage in the passageway of the draft hood and is coupled to deactivate the water heater when a blockage is indicated. 
     In accordance with another aspect of the present invention, a kit for venting a water heater is disclosed. The kit comprises a draft hood configured to be attached to the water heater on top of a blower outlet of the water heater. The draft hood is configured to receive the exhaust gas blown through the blower outlet. 
     In accordance with yet another aspect of the present invention, a method for venting a water heater is disclosed. The method comprises blowing exhaust gas outward through a blower outlet of the water heater, and receiving the exhaust gas blown through the outlet with a draft hood positioned on top of the blower outlet. 
     In accordance with still another aspect of the present invention, a method for configuring a vented water heating system to detect a blockage in a passageway of a draft hood is disclosed. The method comprises positioning a thermal switch downstream of a blower of the water heating system, the thermal switch positioned to detect a blockage in the passageway of the draft hood, and coupling the thermal switch to the water heating system such that the thermal switch is operable to shut down the water heating system when the thermal switch senses a temperature above a predetermined limit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is best understood from the following detailed description when read in connection with the accompanying drawings, with like elements having the same reference numerals. When a plurality of similar elements are present, a single reference numeral may be assigned to the plurality of similar elements with a small letter designation referring to specific elements. When referring to the elements collectively or to a non-specific one or more of the elements, the small letter designation may be dropped. This emphasizes that according to common practice, the various features of the drawings are not drawn to scale unless otherwise indicated. On the contrary, the dimensions of the various features may be expanded or reduced for clarity. Included in the drawings are the following figures: 
         FIG. 1  is a cross-sectional diagram illustrating an exemplary water heater in accordance with aspects of the present invention; 
         FIG. 2  is a diagram illustrating an exemplary system for venting a water heater in accordance with aspects of the present invention; and 
         FIG. 3  is a flow chart illustrating an exemplary method for venting a water heater in accordance with aspects of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Aspects of the present invention relate to the ventilation of powered, atmospherically-vented water heaters. As used herein, the term “powered” in relation to ventilation refers to water heaters having a powered device, such as one or more blowers or fans, positioned to propel exhaust gas away from the combustion chamber and out of the water heater. Further, as used herein, the term “atmospherically-vented” refers to water heaters that vent exhaust gas to the atmosphere via non-positive static pressure venting. 
     While the systems and methods disclosed herein are described with respect to conventional water heaters, it will be understood that the invention is not limited to devices for heating water (i.e. H 2 O). As used herein, the term “water heater” is intended to comprise any device adapted to generate and maintain a source of heated fluid. 
     Generally, the disclosed systems and methods utilize a draft hood positioned on top of the blower to improve the water heater&#39;s resistance to downdrafts. The draft hood enables the creation of negative pressure adjacent the blower outlet. The draft hood desirably includes a thermal switch coupled to the draft hood to monitor the flow of exhaust gas away from the water heater, and control operation of the water heater accordingly. 
     Referring now to the drawings,  FIG. 1  illustrates an exemplary water heater  10  in accordance with aspects of the present invention. Water heater  10  is a powered, fuel-fired, atmospherically-vented water heater. As shown in  FIG. 1 , water heater  10  includes an exemplary system  100  for venting a water heater in accordance with aspects of the present invention.  FIG. 2  illustrates system  100  in more detail. As a general overview, venting system  100  includes a blower  120  and a draft hood  140 . Additional details of venting system  100  are described below. 
     Blower  120  propels exhaust gas away from the combustion chamber of water heater  10 . Blower  120  includes a blower inlet  122  and a blower outlet  124 . Blower  120  further includes an impeller  126  (e.g., a fan) for propelling the exhaust gas. Impeller  126  is powered by motor  128 . Through operation of impeller  126 , blower  120  is operable to draw exhaust gas inward from the combustion chamber through blower inlet  122 , and blow the exhaust gas outward through blower outlet  124 . 
     In an exemplary embodiment, blower  120  is positioned within a top portion of water heater  10 . The size and positioning of blower inlet  122  and blower outlet  124 , as well as the selection of a suitable impeller  126 , may be selected based on the quantity of exhaust gas to be vented by blower  120 . Suitable blowers  120  will be known to one of ordinary skill in the art from the description herein. 
     Draft hood  140  is positioned on top of blower outlet  124 . Draft hood  140  is configured to receive the exhaust gas that is blown outward through blower outlet  124 . In an exemplary embodiment, draft hood  140  includes a flared portion  142 . Flared portion  142  is coupled to a pipe  144 . Flared portion  142  opens toward blower outlet  124 . Desirably, flared portion  142  is positioned so as to be concentric with blower outlet  124 . Pipe  144  extends from the narrow end of flared portion  142  away from water heater  10 . 
     Draft hood  140  may be mounted to blower  120  via one or more mounting structures  146 . Mounting structures  146  may include bolts, screws, or any other structure adapted to affix draft hood  140  to blower  120 . 
     As shown in  FIG. 2 , draft hood  140  is spaced from blower  120  by relief openings  148 . Relief openings  148  enable communication of the exhaust gas blown through blower outlet  124  with the atmosphere surrounding water heater  10  and draft hood  140 . This may be desirable in order to allow dilution of exhaust gas within draft hood  140 , and to allow relief of any down drafts. Mounting structures  146  affix draft hood  140  at a predetermined distance from blower  120 , in order to create relief openings  148  between the edge of flared portion  142  and blower  120 . Mounting structures  146  may include a spacer in order to create relief openings  148  between draft hood  140  and blower  120 . 
     Venting system  100  may further include a thermal switch  160 . Thermal switch  160  is coupled to draft hood  140 . Thermal switch  160  is operable to sense a temperature of the air located in relief openings  148 . As will be further described herein, thermal switch  160  is calibrated to shut down (or stop the operation of) water heater  10  when thermal switch  160  is senses a temperature above a predetermined limit. Thermal switch  160  includes electrical connections  162  for connecting to, and thereby controlling the operation of, water heater  10 . 
     As shown in  FIG. 2 , thermal switch  160  is directly coupled to mounting structures  146  of draft hood  140 . Thermal switch  160  may employ a bracket for mounting thermal switch  160  to draft hood  140 . In particular, thermal switch  160  may be positioned in relief openings  148 . This position may be desirable in order to best sense the temperature of the air located in relief openings  148 . In an exemplary embodiment, thermal switch  160  comprises an air temperature sensor and a memory for storing the predetermined limit. Thermal switch  160  may be a normally closed (NC) manual reset bi-metal switch. Alternatively, thermal switch  160  may be an automatic reset switch. 
     The operation of venting system  100  will now be described with respect to  FIGS. 1 and 2 . During normal operation, water heater  10  burns fuel in its combustion chamber in order to generate and maintain hot water. This burning of fuel creates exhaust gas which is vented by venting system  100 . In particular, impeller  126  draws exhaust gas inward from the combustion chamber through blower inlet  122 , and blows the exhaust gas outward through blower outlet  124 . The exhaust gas blown outward through blower outlet  124  is received by draft hood  140 . During normal operation, all of the exhaust gas flows into flared portion  142  of draft hood  140  and upward through pipe  144 . When there is a vent blockage, exhaust gas may also flow outward through relief openings  148  to the atmosphere surrounding water heater  10  and draft hood  140 . 
     During this operation, thermal switch  160  senses the temperature of the exhaust gas. Thermal switch  160  has a predetermined limit temperature. This temperature is selected based on safety concerns. The selection of a suitable predetermined limit will be known to one of ordinary skill in the art from the description herein. When thermal switch  160  senses that the air temperature in relief openings  148  exceeds the predetermined limit (for example, if the draft hood  140  were to become blocked), thermal switch  160  sends a shutdown signal to water heater  10  using electrical connections  162 . Water heater  10  then stops burning fuel in the combustion chamber, and thereby, stops creating exhaust gas. Water heater  10  may stop burning fuel for a predetermined period of time, or until reset by a user of water heater  10 . 
     The above described system may also form the basis of a kit for venting a water heater in accordance with aspects of the present invention. The kit includes a draft hood configured to be attached to a water heater on top of a blower outlet of the water heater. The draft hood is configured to receive exhaust gas blown through the blower outlet of the water heater. The draft hood of this kit may comprise any of the features described above with respect to draft hood  140 . 
     The kit may further include a thermal switch coupled to the draft hood. The thermal switch is configured to be electrically coupled to the water heater. For example, the thermal switch may include electrical connections adapted to be connected with circuitry of the water heater. The thermal switch of this kit may comprise any of the features described above with respect to thermal switch  160 . 
       FIG. 3  is a flow chart illustrating an exemplary method  200  for venting a water heater in accordance with aspects of the present invention. As a general overview, method  200  includes blowing exhaust gas through a blower outlet and receive the exhaust gas with a draft hood. Additional details of method  200  are described below with respect to system  100 . 
     In step  210 , exhaust gas is blown outward through a blower outlet of the water heater. In an exemplary embodiment, impeller  126  draws exhaust gas inward from the combustion chamber through blower inlet  122 , and blows the exhaust gas outward through blower outlet  124 . 
     In step  220 , the exhaust gas blown outward through the blower outlet is received with a draft hood positioned on top of the blower outlet. In an exemplary embodiment, draft hood  140  is positioned to receive the exhaust gas blown outward through blower outlet  124 . 
     Method  200  is not limited to the above steps, but may include addition steps as set forth. below. 
     For example, method  200  may include the step of enabling communication of the exhaust gas blown through the blower outlet with atmosphere surrounding the draft hood. In an exemplary embodiment, draft hood defines relief openings  148  between the flared portion  142  of draft hood  140  and blower  120 . During a blocked vent condition, relief openings  148  may enable communication of the exhaust gas blown through blower outlet  124  with the atmosphere surrounding water heater  10  and draft hood  140 . 
     For another example, method  200  may include the steps of sensing a temperature adjacent the draft hood with a thermal switch, and shutting down the water heater when the thermal switch senses a temperature above a predetermined limit. In an exemplary embodiment, thermal switch  160  is coupled to draft hood  140 , as described above. When thermal switch  160  senses that the air temperature in relief openings  148  exceeds the predetermined limit, thermal switch  160  sends a shutdown signal to water heater  10  using electrical connections  162 . 
     Although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.