Abstract: A low NOx burner includes an upper plate and a lower plate joined together. A chamber is defined between an upper inner portion and a lower inner portion. The peaks of upper and lower scalloped ridges are in contact such that multiple ports are defined. The ports extend radially outward from the chamber. The chamber is adapted to receive a fuel/air mixture through a fuel/air intake opening. The ports permit a flow of the fuel/air mixture from the chamber for combustion to create a diffuse flame. An intermediate portion is positioned such that the flame attaches to the intermediate portion. The intermediate portion and a trough are arranged such that flame is directed downwards to the trough from the intermediate portion and attaches to the trough. An outer rim is positioned and angled to attach the flame to the trough and to direct the flame upwards from the trough.

Abstract: A manifold for a heat exchanger including a plurality of substantially identical heating tubes. The manifold has front and rear walls. The rear wall has therein a plurality of inlet ports, each of which is adapted to be connected to the outlet of one of the heating tubes, the inlet ports being generally equally spaced along the rear wall in the upper half of the manifold. The rear wall also has therein a plurality of outlet ports, each of which is adapted to be connected to the inlet of one of the heating tubes, the outlet ports being generally equally spaced along the rear wall in the lower half of the manifold. The front wall has therein a water inlet opening into both the upper manifold half and the lower manifold half, and a water outlet spaced horizontally from the water inlet and opening into both the upper manifold half and the lower manifold half.