Harry Smith wrote:
Hi,

A friend who owns her own home asked me to look at her water heater.
The pilot had gone out, and she called the gas company. They sent
someone out who replaced the thermocouple (right term?). Not long
after, she noticed a bad smell and sooty scorch marks above the burner
cover. She turned it off immediately of course.

I have looked at it and read the instructions. The pilot lights and
stays lit. The burner flame lights when it is turned on, but the
flame is very orange and sputtery. Flames lick all around the
underneath and threaten to come out the burner cover. It improves
slightly if the damper is closed, but the room still smells scorched
and sooty. The burner does not appear clogged, though the inside of
the chamber is very sooty and caked.

This isn't behavior you like to see in a major household appliance.
Should she expect to have to replace the unit, or is there a
reasonable shot at repair? It is an older unit of unknown age.

Thanks,
Harry


The "bad smell" is very characteristic of poor combustion.
In this case, either the chimney is blocked or (likely)
the heater's central flue has collapsed.

If you remove the draft hood, you can look down the flue
in the heater to discover.

Flue collapse is caused by old age and/or very high tank pressure.

Jim