|Joined: ||Sat Sep 11th, 2004|
|Improper venting can cause that. So can sooting. If the floor around the water heater is very dirty or the heater is near a laundry dryer, you can get stuff sucked into the burner, fouling it and causing it to burn gas incompletely. That soots up the combustion chamber and flue and the more soot, the worse it gets.
Have a plumber clean the burner and those areas and check to see if there is enough make-up air in the water heater space. Then check to see if the vent is the same size as the water heater flue and if there are any obstructions.
This is a very dangerous situation. You should DO THIS NOW!