Abstract: A low NOx water heater including a water container; a combustion chamber adjacent the water container having an opening covered with an open flame arrestor; a burner associated with the combustion chamber and arranged to combust fuel to heat water in the water container, the burner including a plenum chamber having a combustion surface and a fuel/air conduit adapted to receive fuel and air and extending between and sealed to the plenum and a wall of the combustion chamber; and a heat resistant acoustic absorber positioned on the wall.

Abstract: A water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber, a blower located to receive combustion products generated by the burner, an intake air conduit connected to the combustion chamber and having a combustion air intake opening, a dilution air conduit connected to the blower and having a dilution air intake opening; and a flammable vapor sensor having at least an operative portion positioned in the blower or the dilution air conduit.

Abstract: A water heater including a water container, a combustion chamber adjacent the water container, a burner associated with the combustion chamber, a flue gas collector located to receive flue gases generated in the combustion chamber, a CO sensor having at least an operative portion proximate the flue gas collector, a flammable vapor sensor having at least an operative portion positioned proximate a location where combustion air enters the combustion chamber, and a controller operatively connected to the CO and flammable vapor sensors and adapted to receive signals generated by the CO and flammable vapor sensors and responsively shut off combustion in the combustion chamber.