Originally Posted By: rcallis This post was automatically imported from our archived forum.
The air/gas mix is what causes the orange flame.
Start by removing the burner tubes and cleaning them then look for lint, spider webs, or something around the air shutter. Also, check the gas pressure.
I'd refer this to an HVAC tech for a good cleaning and tune up.
Originally Posted By: dbowers This post was automatically imported from our archived forum.
Jeffrey -
As soon as you saw the ash or carbon or ??? You were basically done with your inspection. You would write up the ABNORMAL condition of the burners and the ABNORMAL flame pattern - THEN - recommend that a COMPETENT and licensed heating contractor service, evaluate and repair the system as needed. You would also recommend they verify the proper operation of the venting system and full integrity of the heat exchanger.
Originally Posted By: jwortham This post was automatically imported from our archived forum.
Dan,
Already told them to have it checked/serviced. 
I am very much a "Why did this happen?" kind of guy versus a "It's abnormal, get it checked". I knew the flame pattern and ash were indicative of problems, just wanted to know what kind of problems for my own knowledge.
Originally Posted By: dvalley This post was automatically imported from our archived forum.
Quote:
I am very much a "Why did this happen?" kind of guy versus a "It's abnormal, get it checked". I knew the flame pattern and ash were indicative of problems, just wanted to know what kind of problems for my own knowledge.
This build-up occurs because an orange flame is both dirty and inefficient, and the ash build-up you are seeing indicates that there is not enough air for combustion, so ash builds up on top of these burners.
On the other hand, a very light blue flame that is sputtering, and hissing indicates there is too much combustion air. The optimum amount of air produces a blue, quiet flame and will not leave an ash build-up atop the burners.
You also stated...
Quote:
Would the ash (I assume that's what the white material is) and the orange flame be indicative of a venting issue?
The only venting issue that you should be concerned with on this particular unit is weather or not it's venting to the outside properly. An improper burn will allow carbon monoxide into a living area on an improperly vented furnace. Improper venting does not cause this gray ash build-up.