9. In case of oil fired boiler, the excess air is usually
A. 75 to 125 percent
B. 5 to 12 percent
C. 1 to 2 percent
D. 20 to 25 percent
9. In case of oil fired boiler, the excess air is usually
A. 75 to 125 percent
B. 5 to 12 percent
C. 1 to 2 percent
D. 20 to 25 percent