Atwood water heater sooting

[nomad10th]

I have a 6gal. Atwood water that is blowing out black soot which is evident seeing the black ash on the exhaust fins and some on the paint outside of the exhaust grille and up the side of the MH. Is this something serious or is it within my ability to fix/clean without taking it somewhere? I found this on Motleyrvrepair.com "It is not uncommon to start the heater and never actually check the outside of the coach where the water heater is. You should occasionally check the exhaust of your water heater for black soot. This can be caused by several things such as LP gas pressure, a dirty orifice, a dirty burner of flue tube, a misaligned burner or burner flame spreader, bad air adjustment or an obstructed exhaust grill. You will need to use your own judgment as to whether to seek professional assistance at this point. Most people do not have the proper tools to address many of these malfunctions. Periodic servicing of the water heater will help insure the most efficent performance."
Has anyone had this problem?

[palehorse89]

Manual here Atwood Water Heater Troubleshooting
Look at the burner and sooting problems.

[nomad10th]

Thanks a bunch..!! Reading the manual you attached, there are some pretty easy checks that I can tackle to figure out what is going on.

[paz]

The first thing I would look for is a spider nest obstructing the air flow in the burner tube. If that didn't turn up anything, I would next check the orifice. LP gas is a byproduct of refining oil, and it sometimes contains dark, gooey residue that can clog the orifice. Other times, the orifice will be blocked by a gray, ash-like substance.

[targaboat]

Soot indicated a lack of air flow to the propane flame. Start where the air inters and follow its path through the tubes inside the tank and out the exhaust. You may have to figure out a tool to go through the tube inside the tank. Could be a critter has tried to make home in there.

[nomad10th]

Thanks guys.