Rust under draft hood of water heater

[Joe Van Orsdol]

I'm looking at an 11 year old water heater.  It shares it's vent with a 50+ year old gas fired boiler.  Does this rust come our of the water heater flue and is evidence of an old appliance?

[David Macy]

Do you have any pics of the flue of the boiler and water heater?

What did the chimney look like, was it capped at the exterior?

I would guess the 50 year old boiler is probably the cause of the rust/debris.

I would think a clean and check of the boiler and flue would be a good recommendation.

Also did you check the appliances for backd rafting with a mirror or some other method of checking.

[Richard Fitzwater]

I have seen moisture from condensation in cool areas cause rust on flue pipes.