ULTRA LOW NOx WATER HEATER

Abstract

A low NO x water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container, the burner comprising a plenum chamber having a combustion surface and a fuel/air conduit adapted to receive fuel and air, and a fuel nozzle positioned to supply fuel into the fuel/air conduit at an angle that is between about 1.5° and about 2.5° out of horizontal relative to a horizontal plane extending along a central axis of the fuel/air conduit.

1 . A low NO x  water heater comprising:
 a water container;   a combustion chamber adjacent the water container;   a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container, the burner comprising a plenum chamber having a combustion surface and a fuel/air conduit adapted to receive fuel and air; and   a fuel nozzle positioned to supply fuel into the fuel/air conduit at an angle that is between about 1.5° and about 2.5° out of horizontal relative to a horizontal plane extending along a central axis of the fuel/air conduit.   
   
   
       2 . The water heater defined in  claim 1 , wherein the angle is about 2°. 
   
   
       3 . The water defined in  claim 1 , wherein an end portion of the fuel/air conduit extending from the plenum is sealed to a wall portion of the combustion chamber. 
   
   
       4 . The water heater defined in  claim 3 , wherein the wall portion is a door sealed to an opening in the combustion chamber. 
   
   
       5 . The water heater defined in  claim 1 , wherein the fuel/air conduit extends into the plenum a distance of about ¾ of the length of the plenum. 
   
   
       6 . The water heater defined in  claim 5 , wherein a distal portion of the fuel/air conduit extending into the plenum is angled at about 45°. 
   
   
       7 . The water heater defined in  claim 1  wherein the angle is less than 3% out of horizontal relative to the horizontal plane extending along the central axis of the fuel/air conduit. 
   
   
       8 . The water heater defined in  claim 6  wherein a top portion of the distal portion of the fuel/air conduit extends further into the plenum than a bottom portion of the distal portion of the fuel-air conduit. 
   
   
       9 . A low NO x  water heater comprising:
 a water container;   a combustion chamber adjacent the water container;   a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container, the burner comprising a plenum chamber having a combustion surface and a fuel/air conduit adapted to receive fuel and air; and   a fuel nozzle positioned to supply fuel into the fuel/air conduit at an angle that is greater than 0° and less than 3° out of horizontal relative to a horizontal plane extending along a central axis of the fuel/air conduit.