Bosch Evolution 300 Series Service Manual page 9

Surface Burner Flame Characteristics
A properly operating burner will have clean blue flames with no yellow
Photo %
tipping, excessive noise or lifting away from the burner head. Photo B
at right illustrates a typical flame at high setting.
B
Yellow flames indicate improper fueltoair ratio and can be caused by
improper gas pressure, improper conversion for use with LP gas or
contaminated fuel supply. 6HH 6XUIDFH %XUQHU )ODPH $GMXVWPHQW IRU
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