The sequence of burner during lighting up and shutting down of boiler furnace plays an important part in ensuring the stability of temperature distribution in the boiler. Changing burner arrangement is unavoidable in power generation industry since the number of burner used depends on the capacity of load generated. This paper describes an analysis on the influence of burners arrangement to the flow and temperature distribution at furnace re-heater. Simulation is performed using general CFD code, CFD ACE+. The boiler under investigation is a 120 MW gas fired boiler. It is of tangential type where fuel and air are fired from its 4 corners. The operating condition of the actual furnace is used as the boundary conditions. Prediction of flow and temperature distribution shows good qualitative agreement with practical observation. The flow inside the furnace is highly swirling, with helical pattern in anti-clockwise direction. Furnace re-heater shows imbalance temperature distribution where the left side of the wall experience higher temperature than the right wall.