[LazyPup]

IF it is just a faint wisp of the odor when the burner first comes on, then dissipates quickly I doubt if there is anything to worry about.

You stated in your original post that you first noticed it while working in the laundry, which is adjacent to the water heater. You probably never noticed it before, buy now that you have you are more conscious of it.

That slight odor will be more pronuounced in winter because the air in the chimney flue is colder and requires a few more moments to preheat to start the draft. Also, it is probably a bit more noticable on days with high barometric pressure as combustion gases are heavier than air which would cause a bit of delay in establishing the draft.

Just to be sure, you may want to examine the flue pipe from the heater to the chimney. Make sure there are no rusted spots, all joints are firmly screwed together, and their is a good 1/4 inch per foot pitch upward from the burner to the chimney. Also make sure the pipe is sealed into the masonary of the chimney wall.

Also measure the length of the run from the top of the heater to the chimney. The horizontal run should not exceed 75% of the chimney height. (If the chimney is 20 feet high the horizontal run should not exceed 15 ft)

Visually inspect the gas flame when the burner is on. The flame should appear a darker blue color near the heater and lighter blue at the top of the flame with just the occasional wisp of yellow tips on the flame.

If you see a substantial amount of yellow on the flame tips you may want to have a service man adust your burner.

If you just get a wisp of the odor when the burner lights, the flue checks out ok, and the burner flame is okay you should not have anything to worry about.