Abstract:
A venting system and a method for installing the venting system. A non-flexible metallic venting pipe comprises a chase. A first end of the vent pipe is positioned adjacent an appliance installation and a second end positioned at an exit to an external region of a home. A flexible vent tube comprising a sealed non-corrosive material, having a first end and a second end, is positioned between the first end of the venting pipe and the second end of the venting pipe. Adapters are positioned at the ends of the venting pipe. A method comprises routing a flexible venting tube comprising sealed, corrosion resistant venting material through an existing non-flexible double-walled vent comprising non-sealed material.

Description:
BACKGROUND 
       [0001]    Vent systems are used with various types of exhaust producing appliances. Generally, vent systems operate as negative draft systems or as positive pressure systems. 
         [0002]    Vent systems are divided into various categories. A Category I vent system operates with a negative draft, and the products of combustion are hot enough to stay well above dew point. Since a major portion of gas flue products is water vapor, condensing can occur when the flue products are allowed to cool below dew point. This can cause corrosion if the wrong materials are used in the vent system. A Category I vent system is typically vented with Type “B” vent materials. 
         [0003]    A Category II vent system also operates with a negative pressure in the vent, but the temperature of the flue products has cooled to a point where they may condense into a liquid in the flue. A Category II vent requires vent materials that are resistant to the corrosive effects of flue gas condensate. 
         [0004]    Category III and IV vent systems operate with a positive pressure in the vent system. Positive pressure vents must be fully sealed to prevent spillage of flue products into an occupied portion of the building. A Category III vent system maintains flue gas temperatures above dew point and should not condense in the flue. A Category IV vent system&#39;s flue products cool below their dew point, therefore it is possible they may condense in the flue. 
         [0005]    Material selection and sizing for the vent system of a Category II, III or IV boiler is determined by the information contained in the manufacturer&#39;s installation instructions, which is based on performance testing under the requirements of the ANSI standard. 
         [0006]    All vent systems other than Category I generally use heat and corrosion resistant materials, which are typically more expensive. Category IV vent materials are typically fully sealed and constructed from heat and corrosion resistant stainless steel to withstand the possible corrosive effects from acidic flue gas condensate. 
       SUMMARY 
       [0007]    The technology, roughly described, includes a method for creating a venting system for an appliance. The method includes routing a flexible venting tube comprising a Category II, Category III or Category IV compliant venting material through an existing non-flexible vent comprising a Category I material and coupling the first end of the flexible venting tube to the appliance and the second end of the venting tube to an outlet. 
         [0008]    In a further aspect, the technology comprises a venting system. The system includes a non-flexible metallic venting pipe comprising a chase. The chase includes a first end positioned adjacent an appliance installation and a second end positioned at an exit to an external region of a home. A flexible vent tube comprising a sealed non-corrosive material is provided in the chase. The flexible vent tube has a first end and a second end and is positioned between the first end of the venting pipe and the second end of the venting pipe. A first adapter is positioned at the first end of the venting pipe; and a second adapted is positioned at the second end of the venting pipe. 
         [0009]    This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0010]      FIG. 1  depicts a conventional category I appliance and category I venting system. 
           [0011]      FIG. 2  depicts a conventional Category II, III or IV appliance with the venting system described herein. 
           [0012]      FIG. 3  depicts a conventional Category II, III or IV appliance adapters for use with the venting system described herein. 
           [0013]      FIGS. 4A-4B  are views of a first embodiment of an adapter shown in  FIG. 3 . 
           [0014]      FIGS. 4C and 4D  are a second embodiment of an adapter shown in  FIG. 3 . 
           [0015]      FIG. 5  depicts a conventional Category II, III or IV appliance with a condensate drainage system for use with the venting technology. 
           [0016]      FIG. 6  depicts a conventional Category II, III or IV appliance with a second embodiment of a condensate drainage system for use with the venting technology. 
       
    
    
     DETAILED DESCRIPTION 
       [0017]    Technology is presented enabling a venting system for use with an appliance requiring Category II, III or IV venting specifications. The system utilizes existing venting materials installed in a building to provide clearance and ease in the installation of a venting system suitable for the appliance. 
         [0018]      FIG. 1  depicts a Category  1  venting system  100  coupled to an appliance  190 . The category I system may be comprised of single or double walled pieces  130 ,  140 ,  150 ,  170  in areas where no combustibles are present, but generally, a double walled portion  145  will be provided through any combustibles such as ceiling insulation  125 , ceiling material  120  or roofing material  110 . Double walled portion  145  is typically known as Type-B vent and is suitable for Category I venting purposes. Generally, venting specifications call for at least one inch of clearance between the double walled category I material and such combustibles. Procedures for correctly sizing vents and connectors is published by NFPA in a publication entitled,  NFPA  54 : National Fuel Gas Code  ( NFGC ). The standard for category I gas vents are provided in UL 441, Gas Vents. Standards for venting gas appliances are provided in UL 1738, the United Laboratories Standard for Safety Venting Systems for Gas-Burning Appliances, Categories II, III, and IV-Second Edition; Reprint with Revisions Through and Including Dec. 6, 2000. The vent system terminates in a vent cap  180  on the exterior of a building. Generally the vent cap  180  is sized to couple directly to the vent cap  180 . 
         [0019]    Other components, such as a storm collar for the exterior of the building, fire stop at the ceiling, and appliance details, are not illustrated in  FIG. 1 . 
         [0020]      FIG. 2  illustrates a first embodiment of the present technology. In accordance with the technology, an existing category I venting system  100  is used as a chase and an internal venting material  200  comprising a heat and/or corrosion resistant venting element  200  having a diameter smaller than that of the existing material venting components  130 ,  140 ,  145 ,  150 ,  170  is inserted into the existing system  100 . 
         [0021]    Combined with the use of a first adapter  210  and a second adapter  220 , the venting system comprising venting element  200  and existing system  100  allows coupling a Category II, III or IV appliance through the existing system to the vent cap  180  with relative ease. This allows conversion of, for example, an existing water heater to a “tankless” water heater and improves energy efficiency of a building. 
         [0022]    Internal vent element  200 , in one embodiment, comprises a flexible venting material comprising a heat and/or corrosive resistant material suitable for use in Category II, III or IV systems. Material which is suitable for use in such systems includes AL29-4C stainless steel and Type 444 Stainless steel. Commercial products suitable for use as vent material  200  include varieties of Type 446, 447, 448, 304, and 316 stainless steels. 
         [0023]    Typically, a venting system in accordance with the present technology will be necessitated by replacement of the Category I appliance with a different type of appliance. During installation, the existing vent system is uncoupled from the gas appliance. Likewise, the vent cap  180  is decoupled from the existing vent system. The venting material  200  is then snaked though the existing system using the existing system as a chase until the lead end of the material reaches the end of the vent system near the vent cap  180 . 
         [0024]    It will be understood that the vent system  100  may be comprised of various types of materials having different cross sections. In one embodiment, the vent pieces have circular cross-sections. In an alternative embodiment, the vent pieces have oblong cross sections. 
         [0025]    Vent material  200  is comprised of a vent material having a diameter or cross-section suitably sized to fit within all components of the vent system  100 . The difference between the cross-sectional size of the vent system  100  components and that of the vent material  200  can be as small as minimal as that sufficient to allow the flexible vent pipe to fit inside the interior of the exterior vent pipe. Typical type-b vent installations range from diameters of 3″ to 8″. Flexible material suitable for use as vent material  200  includes DuraFlex brand flexible stainless steel products from Simpson Duravent Corporation. 
         [0026]    Once vent material  200  is positioned in vent system  100 , a first end of the material may be coupled to a Category II, III or IV appliance  290 , while the second end is coupled to the vent cap  180 . In one embodiment, the vent material  200  may be coupled directly to the apparatus coupling on the appliance  290  and the vent cap  180 . Vent cap  180  may need to be adapted from the larger diameter coupling of the existing vent system  100  to the smaller sized coupling of the vent material  200 . Typically coupling to the vent cap  180  will require a sizing adapter, such as that shown in  FIGS. 3-4B , since the size of the vent cap coupling will have been sized for the original vent pipe  145 . Alternatively, a specially sized vent cap may be coupled to the vent material  200 , replacing the vent cap  180 . It will be recognized that additional Category II, III or IV venting material may be provided at the end of the vent section. In particular, the upper vent adapter  220  have one side coupled to seal the end of the existing system  100 , while the second side is coupled to a rigid vent section of Cat II, III, IV pip (not shown) to which is attached cap  180 . This embodiment allows an extension of the new vent system which may exceed the height of the existing vent system. 
         [0027]    It will be recognized that a gap now exists between the exterior of vent material  200  and the interior wall of the vent system components  130 ,  140 ,  150 ,  170 . It may be advantageous to seal this region using adapters  210 ,  220 . 
         [0028]      FIGS. 3-4B  illustrate the use of adapters  210 ,  220  with the venting system according to the present technology. As shown in  FIG. 3 , a first adapter  220  may be positioned between one end of the vent material  200  and the vent cap  180 , or between vent  200  and a vent pipe extension (not shown) and cap  180 . A second adapter  210  is positioned between a second end of the vent material  200  and the appliance connector  295   
         [0029]      FIG. 4A  is an isometric view and  FIG. 4B  is a cross-sectional view along line B-B in  FIG. 4A  of a typical adapter for use in the present technology. The adapter has an outer ring  410  positioned to surround the end of the outer vent component, such as component  210 . An adapter fitting  420  allows the inner vent material  200  to be coupled to the adapter. Coupling the inner vent material to the fitting  420  and the outer ring to the outer vent material seals one end existing vent system  100 . An outer fitting  430  is providing to couple the adapter to the appliance. In a similar manner, a second adapter  210  uses an inner fitting  420  to couple the second end of the inner vent material  200  and an outer fitting to engage the vent cap  180 . 
         [0030]    In the illustration in  FIG. 4A ,  4 B and  FIG. 3 , the outer fitting appears with the same diameter as the inner fitting. However, it will be recognized that the inner fitting  420  and the outer fitting  430  may have different sizes, and cross-sectional shapes, depending on the components to which they are to be coupled. An adapter with different diameter inner and outer fittings is illustrated in  FIGS. 4C and 4D . The adapter used in  FIGS. 4C and 4D  is useful where, for example, the vent cap  180  is designed to be used with the larger diameter of the existing vent system components  100 . 
         [0031]    While each adapter  210 ,  220  is discussed herein as being equivalent in structure, it will be recognized that each adapter may be appropriately sized depending on the diameter of the components of vent system  100  as well as the vent material  200 . In addition, although the vent adapters are illustrated as having a generally circular shape, the cross-section of the adapter will be formed to match the shape of the interior vent material  200  cross-section as well as well as the vent system  100  cross section. 
         [0032]      FIGS. 5 and 6  illustrate various embodiments of a condensate drain adapter for use with the present technology. If a Category II or IV system is in use, condensate may accumulate in the inner vent material  200  and some form of drainage system must be provided to remove the condensate from the vent system.  FIG. 5  illustrates an embodiment wherein the Category II or IV vent material components are couple to an adapter positioned at the end of the existing category I system. In the system of  FIG. 5 , the existing system  100  is used for the limited purpose of extending the interior vent material  200  though combustibles. Accessible portions of the building may allow for installation of additional components  550  of Category II, III or IV materials leading to the coupling with the appliance  290 . In the embodiment of  FIG. 5 , a condensate drain adapter  510  allows the coupling of a drainage hose  520  to a spigot  530  to remove condensate to a drain  540 .  FIG. 5  also illustrates that use of the existing vent system  100  allows maintaining the existing flashing and storm collar, further easing the installation of the venting system when installing a new Category II, III or IV appliance. 
         [0033]      FIG. 6  illustrates an alternative use of a t-adapter  590  having condensate drain spigot adapted in the same manner as the system of  FIG. 5  to couple a drainage hose  520  to a spigot  530  to remove condensate to a drain  540 .