The low NOx and CO emission gas burner has been created so that it complies with European standard EN676 class III. It has a two-stage operation with either a high or low flame. It has a ventilation efficiency that is high and also low electrical input. The exhaust gas recycling blast-pipe is able to achieve low pollutant emission. The mixing unit can be removed without actually removing the burner and that facilitates easy maintenance. The regulation of air flow rate for first and second stage by closing the damper is on standby to prevent in-flue heat dispersion. Electrically controlled, one-stage operating valve regulates gas. The burner is equipped with a 4 and 7-pole connector, a flange and an insulating seal for boiler fastening.