2005 25' International water heater

[rebelhoop]

My water heater somehow over fueled and blackened the grate vent and left sooty marks up the side of the trailer about 12" I don't think I have a vent to roof pipe that might be blocked, it simply vents thru the door grate. Is the small valve in the heater simply a shutoff valve or does it regulate too? It seems to be working fine now, I'm suspicious of my main regulator being 12 years old, any thoughts on this?

[AlinCal]

The valve is only a shutoff.
Spiders will build nests inside burner tube that cause trouble sometimes.

[rebelhoop]

Thanks! I'll clean that area.