Soot from Atwood water heater pilot light
There's always some little issue with our trailer when I get back to it after abandoning it for 8 months in FL, and this year was no exception.
The water heater started and ran perfectly, with a good blue flame, but the pilot light was yellow, large, and lazy. After a day there was enough soot build-up to fill a teaspoon. This cool flame was insufficiently hot to quieten the automatic re-lighter, and this was sparking constantly.
On the front of the gas valve is a screw marked "pilot adjust", but when I removed the Torx screw, as instructed in the manual, there was no adjuster screw underneath. I searched this forum, but could find no mention of this precise issue. A Google search revealed one suggestion that a dirty main burner tube could upset the air flows and cause the yellow pilot; however, I had dismantled and cleaned the main burner tube. The Google search also revealed on the Atwood site that "no attempt should be made to adjust the pilot flame."
I therefore again dismantled the main burner and pilot assembly for inspection. I noticed that the pilot light tube was constructed as a Bunsen Burner, with a small fixed size air hole in the side of the pilot tube. This hole was normally concealed from view. I deduced that if this hole was partially blocked, then the symptoms would be as described. I could see no blockage, but the tube is narrow, and the partial flap at the flame end makes it difficult to inspect. I therefore dismantled the pilot tube using a wrench, and laid the tube on the bench for inspection. I used a wooden toothpick to slide down the tube to clean it, and then blew down it from both ends.
I reassembled the pilot and burner tube. The water heater pilot is now blue, the automatic re-lighter is content, and so am I. I suspect this problem has been gradually building up for a few years. I report this isssue in case there are others with soot building up from an air-starved pilot light.
Nick Crowhurst, Excella 25 1988, Dodge Ram 2500 Cummins Diesel. England in summer, USA in winter.
"The price of freedom is eternal maintenance."