Water heater : is this normal?

[cazual6]

On my last trip, at night, I smelled plastic burning. Couldn't find where it was or where it came from. But I had hot water. The next day it was cleaned up by my RV washer and didn't get a chance to take a picture of how bad the black burnt smoke came up. This is all for left. Is there suppose to be black burnt smoke out of the water heater section? If not, what should I look for?

[dkottum]

Open the hatch and look at the flame when burning. It should be blue. If it is yellow to red it is too rich with fuel, lean with oxygen and will produce less heat and black sooty smoke.

You can adjust it by loosening the screw that secures a sliding sleeve over the flame and move it until it produces a nice blue flame.

The mixture may change with a change in altitude or ambient temperature and require adjustments for optimum performance.

[OTRA15]

You may have spider or mud dauber nests inside the burner tube, and/or inside the exhaust flue which runs inside the heater. We just went through something similar, as detailed in Posts #1804 and 1802 on the 20-footer thread:

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"I just happened to be sitting in our trailer a few weeks ago when I turned everything on . . . and heard the water heater making all kinds of sputtering noises, plus producing dark black smoke. I quickly turned off the switch in the bath, and went outside to find dark smoke stains on the exhaust part of the flue and on the back of the exterior louvered door.

Figuring there were probably nests of some kind in the flue, I cranked the compressor up to about 80 PSI and blew out the flue, after first taking the burner tube off to get better access to the flue right behind the igniter.

I also cleaned out the burner tube and adjusted the LP/air mixture as noted in the earlier quote . . "
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"We just had a problem with ignition in the LP mode, so in addition to cleaning out the burner tube and sending compressed air up the flue inside the water heater, I also adjusted the air mix tube until the flame stopped sputtering and was a clean steady blue flame. In ours, the tube needed to be slid to the right, which resulted in less air mixing with the propane as it entered the burner tube. This adjustment is now at the end of its adjustment FWIW."
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Your owner's manual may have some info on this in the plumbing or appliance section about the water heater. Similar insect nests can also mess up the flues for the fridge and furnace in some models, so if you have insects in one location they may in others. They like the warm spots for a home.

Good luck!

Peter

PS -- Search results for "spider insect nests flue" via the blue search box above -- remove one or two search terms for more results:

https://www.google.com/search?q=spid...=airforums.com