单项选择题
A.carbon deposits on the flame scanner
B.high fuel oil temperature
C.low fuel oil viscosity
D.high steam pressure
单项选择题 Heavy soot accumulations in an auxiliary boiler could be caused by（）
单项选择题 The purpose of the programmed purge cycle on an automatically fired auxiliary boiler is to（）
单项选择题 The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to（）