A method and fuel supply system for supply of a combustion chamber with at least one combustible fluid are provided. The fuel supply system includes a combustion chamber, at least one supply circuit, and at least one purge circuit, the purge circuit coupled to the at least one supply circuit, the purge circuit including at least two isolation valves defining a cavity between, a source of relatively high temperature purge air coupled in flow communication to the cavity through one of the at least two isolation valves, a source of relatively low temperature ventilation air coupled in flow communication to the cavity, and a vent coupled in flow communication to the cavity, the at least one purge circuit configured to channel a flow of relatively low temperature ventilation air from the source relatively low temperature ventilation air through the cavity to the vent during operation of the combustion chamber.