A burner for use with an igniter for firing a flame into a heat-exchanger includes a body having a sidewall that defines an interior chamber. A first opening in the body receives a pre-mixed mixture of air and fuel. A second opening in the body is in fluid communication with the first opening. A distributor connected to the body closes the second opening. The distributor includes a first portion and at least one curved second, portion provided on the first portion. Each second portion includes a plurality of first perforations in fluid communication with the first opening in the body. The first perforations of one second portion are positioned adjacent to the igniter such that ignition of the pre-mix mixture flowing through the first perforations results in a flame through the second portion.