Water Heater Soot

[NDILLON]

Hi,
I have a Lochinvar natural gas water heater, 40 gallon, appx. 10 years old. It starting throwing out soot for few days and then stopped. I called a plumber who couldn't find any thing. He said that the exhaust vent pipe (that goes to outside) may have been blocked with a bird or something. He used a low pressure air (nitrogen burst) to clear it up but nothing came out. Plumber said that I need to replace the water heater. Water heater has been working fine, not throwing black soot and no other issues. Do I need a new water heater? Please help.
Thanks

 

[Jadnashua]

Soot implies an incorrect fuel/air mixture. Why that's the case could be from more than one problem. Did he use a fuel:air combustion tester to check that?

 

[Sponsor]

 

[NDILLON]

Soot implies an incorrect fuel/air mixture. Why that's the case could be from more than one problem. Did he use a fuel:air combustion tester to check that?

Soot implies an incorrect fuel/air mixture. Why that's the case could be from more than one problem. Did he use a fuel:air combustion tester to check that?

 

[NDILLON]

He ran couple of tests with a small meter (similar to one used for code reading in cars) and everything was normal.

 

[LLigetfa]

Soot implies an incorrect fuel/air mixture.

I agree. Likely not enough air or too much gas.

If the problem cleared up before the plumber got there, I'm not sure what he/she could see. I'd be more suspect of a clogged intake or a failing gas pressure regulator. Is there two pipes outside, an intake and an exhaust? Something could have temporarily obstructed the intake.

One time my wife placed the dog's blanket on top of a garbage can that was next to the furnace intake. When it was windy, it would flip the blanket up and block the intake. This went on intermittently for days. When I looked, the intake was clear and it never dawned on me that the blanket would flip up. I suspected a bad sensor and told the wife to call the repair guy the next time it happened. The blanket just happened to flip up when he was there.

Any other gas appliances acting up at the same time to suggest a failing regulator?

 

[FullySprinklered]

Exactly where is the soot showing up, Mr. Dillon.

 

[NDILLON]

The black soot is in the area where burner is. I had left the access panel open and soot was coming out of that door.
It makes sense that may be there was not enough air. I live in a townhouse and the water heater is installed in a closet. I used to keep the closet door closed.
All other appliances in the home are working, no issues.
I want to know if I should change burner? Or do I need to get a new water heater ( I am trying to avoid the expense but if it is necessary I will do it).
Thanks everyone!!

 

[Master Plumber Mark]

The orfice of your heater has clogged up and is sending out soot up the chimmney of the heater... this is technically a fire inside the burner chamber
that could melt the gas line to the burner assmebly
you are not considering the soot that has already built up in the baffle system of the heater that should be
pulled out and cleaned... you are wasting your time....the FVIR safety system should have shut down due to the heat and
something more is wrong with the unit

get a new water heater and be done with it.... again you are wasting your time with a 10 year old heater
and the correct burner assembly will almost cost you more than half what a heater will cost....

 

[FullySprinklered]

Don't know where you're at in solving the problem, but I had a w/h replacement a couple of years ago where heat from the existing unit had blistered up the vinyl on the floor to the extent that the bulge had cut off the air to the appliance. There was a large blackened area on the side of the w/h beginning at the access panel and streaking up the side for a couple of feet. There was also an unpleasant smell present when the w/h cycled on according to the tenant.