Yellow tips, yellow flames and soot indicate one of two problems. The equipment hasn't been properly converted to LPG from natural gas (methane) with the appropriate LPG jets supplied with the equipment or bought separately from the manufacturer of the equipment. If natural gas (methane) equipment is connected to butane / propane cylinders or a plumbed in propane cylinder / tank supply, yellow tipping / sooting will be an issue. Natural gas equipment is not designed to run on LPG and LPG equipment is equally not designed to run on natural gas (methane) either, both gases have different BTUs / calorific values and heat outputs and are incompatible with each other. Another cause of sooting and yellow flames / yellow tips on blue flames, is inadequate aeration setting, because LPG needs significantly more air to burn cleanly than natural gas does. LPG equipment properly installed and set up, or natural gas equipment properly converted and set up to run on LPG, shouldn't display yellow tips or deposit soot on pans kettles utensils oven walls or grill sides. However, when running on butane gas cylinders, it is common to see very slight yellow tips at the top of the blue flame on grills and oven burners, but will be largely blue and of even height when using propane gas cylinders.

Thanks

Could have skipped the lecture.