An experimental work has been carried out to study the effect of burner diameter on the heat transfer characteristics of swirling flame impinging on flat surface. The parameters, equivalence ratio (0.8, 1.0 and 1.2), firing rate (4 kW, 5 kW and 6 kW), burner diameter (15 mm, 20 mm and 25 mm) and helical vane swirler (45°) are considered to investigate the heat transfer characteristics on target surface at fixed separation distance. Stagnation point heat flux and radial distribution of heat flux on impinging surface have been obtained. It has been observed that with increase in burner diameter, the heat flux distribution was more in the wall jet region under identical operating conditions.