Corrosion on water heater

[mathew stouffer]

This water heater is 12 years old, basically toast in our area. Anyhow I told the buyer corrosion on the flue vent can be caused by poor venting. Plumber said not likely. Any thoughts.

Mat

[Nick Ostrowski]

It's odd how the corrosion is showing on the cold water inlet and not the hot water outlet. But heat spillage isn't always uniform either. And with the short rise of the flue pipe before it starts to angle towards the chimney, it could play a part in the corrosion. The flue pipe should have 12 inches of vertical rise before angling towards the chimney.

[Jerry McCarthy]

Mathew
I'll call and raise you two-bits! It's the water or should I say the chemicals therein.
Cool site: Water Heaters Information by Contractors Solutions 610-789-0354 Local calls only please (http://www.contractorssolutions.com/Information/WaterHeaters.htm)

[Brandon Whitmore]

The flue pipe should have 12 inches of vertical rise before angling towards the chimney.

I keep hearing this, but can't find anything in the IRC.... anyone have a code source?

I have found this requirement in the installation instructions of one water heater manufacturer.

[mathew stouffer]

Jerry,
I don't have to bits so will you please explain.

[Patrick McCaffery]

Just something to add to the previous comments. Could this be a combination of several factors?
1. It appears that the pipes coming out of the water heater are galvanized, coupled to copper.
2. We notice that there appears to be flaking on the cold water in-let.
3. The vent pipe is above the cold water in-let.
Normally in late spring early summer, condensation occur on the cold water in-lets. Could this be a chemical reaction between the galvanized pipe and the copper piping, caused by condensation?

[bruce m graham III]

There are dielectric unions installed but the "corrosion" is from a water leak.

ps
Nice link Jerry

[Dana Bostick]

As a plumber (now HI) I'm coming down on the side of vent spillage. Poorly installed venting, missing or damaged/blocked vent termination, back draft from wind conditions and too short above the roof, stubbed into old transite vent or combination of above.
DE unions suck and should always be called as well. I've used them in the past and had to go back and replace them.
Dana

[Brandon Chew]

I see a lot of crap piled up under the draft hood and a vent that looks a lot newer than the draft hood or water heater.

[Scott Patterson]

If it was spillage from the vent, you would most likely see signs of it on the cold and hot sides.

The dielectric fitting has failed. It looks like this might have caused a pinhole leak. Also that does not look like a "B" vent pipe. Flue pipe needs to be on the outside of the raised area around the draft collar.

Anyway, at 12 years that WH will most likely die in short order.

[mathew stouffer]

Thanks for the information. Very helpful. Have a great weekend. If anyone skies in Park City let me know I have a place to stay.

mat

[Dana Bostick]

On second look, I agree, the dielectric union has failed. This is the usual state we see these things in.
Dana

[Patrick Martinez]

Dana,
I agree with you on the DE failure, I have used Brass with great success eliminating the corrosion all together. As to the vent, some of the corrosion could very well be poor combustion, and likely creating the runoff of the corrosion down the flue.

Pat