The atmospheres used in a brazing furnace play a critical role in the final quality and metallurgical properties of the brazed component. Typically, exothermic, dissociated ammonia and nitrogen/hydrogen atmospheres are used for brazing mild steel, alloy steel and stainless steel components. The atmosphere composition, flow rates, pressures, and dew point are some of the key variables control final quality. Almost all brazing companies have quality issues that directly result from improper atmosphere application and control. Common problems include oxidation, flashing, inadequate braze flow, sooting, decarburization and carbon pickup. This troubleshooting presentation reviews years of field experience with nitrogen and hydrogen based atmosphere systems. It will help the heat treater or the brazing production engineer to identify these problems and apply appropriate corrective action.