Bosch HDIP054U Use And Care Manual page 16

Yellow Flames:
Further adjustment is required.
Yellow Tips on Outer Cones:
Normal for LP Gas.
Soft Blue Flames:
Normal for Natural Gas.
If the flame is completely or
mostly yellow, verify that the
regulator is set for the correct fuel. After adjustment,
retest.
Some yellow streaking is normal during the initial start-
up. Allow unit to operate 4-5 minutes and re-evaluate
before making adjustments.
Figure 3: Checking Flame Characteristics
Foreign particles in the gas line may cause an orange
flame during initial use. This should disappear with use.
Check burner to make sure port holes are not obstructed. If
the ports are clogged, see "Before Calling for Service" on
page 17.
NOTE:
An audible "pop" may be heard when the burner is turned
off manually. The "popping" may be louder with LP gas than
with natural gas. This is normal.
English 13