Inside of my Buderus DHW Tank

[huffdawg]

Only 7 yrs in service

 

[maple1]

That's pretty scary looking. My father has a Buderus indirect - doesn't look like that though, it's rectangular & horizontal. Does it have an anode rod? Any diagnosis or feedback from Buderus or a dealer on it? That's not very long...

 

[huffdawg]

It had a 14 inch anode rod with lots of life left in it still. I looked into it a while back , the warranty was expired.. I was getting rusty coloured bath water and my boiler water pressure was getting high. Lifting the relief occasionally. Pin hole in the stainless cool. I bought an eighty gallon Eco King to replace it.. the extra 30 gallon capacity makes for easier hot water management..it has a copper coil. We'll see how it lasts.

 

[velvetfoot]

Wow. The stainless rotted?
I've got a reverse indirect (froling Energy). The pipe is 17 gallon capacity corrugated stainless in a 120 gallon tank.
For you, would it just have been the question of whether the coil rots from the outside or inside?
Is the water treated?

 

[huffdawg]

Wow. The stainless rotted?
I've got a reverse indirect (froling Energy). The pipe is 17 gallon capacity corrugated stainless in a 120 gallon tank.
For you, would it just have been the question of whether the coil rots from the outside or inside?
Is the water treated?

The boilerwater isn't treated, judging by the condition in side the tank is bet it was the DHW.

 

[velvetfoot]

That's what I meant...is the dhw treated?

 

[peakbagger]

Wow, that sure looks like one of two things, you have really aggressive water or a design flaw.

 

[jebatty]

Not unusual for DW to be mildly acidic or basic, pH from 6 to 8.5. A pool water test kit may provide useful info on pH, softness and other parameters of your DW. Acidic water can be very corrosive.

 

[huffdawg]

That's what I meant...is the dhw treated?

It's only treated with chlorine as far as I know.. And I know they overdose it.

 

[Highbeam]

Chlorinated water can be very corrosive. It's like a salt. If you can drink it then it shouldn't be too bad though and Stainless should tolerate it well.

 

[peakbagger]

There is a such a thing as stress corrosion cracking https://en.wikipedia.org/wiki/Stress_corrosion_cracking that can screw up stainless especially when chlorides are around. Plus there is potential crevice corrosion that can occur when stainless is worked with carbon steel tools and rust gets forced into the SS surface. Far more likely is they outsourced the manufacture of the coils and the alloy quality was crap. Not the first time I have seen stainless fail related to someone saving a buck by buying low quality SS alloy. 25 years ago Brazilian SS flooded the market and it had some real issues. No doubt Chinese stainless has also had its issues.

 

[Fred61]

In our neck of the woods reservoir water tends to be more acidic for obvious reasons and ground water tends to be more basic because of the limestone.

 

[Highbeam]

In our neck of the woods reservoir water tends to be more acidic for obvious reasons and ground water tends to be more basic because of the limestone.

So acid rain washed into the ground and dissolves the limestone. Makes some great caves and sinkholes! Surface water is acidic here too but not as bad. Just bad enough to dissolve copper and lead from plumbing though. Too much of that and we get excessive emissions of copper/lead from the sewage treatment plant. Then I get a call to add sodium hydroxide to the drinking water and bring up the pH.

 

[Bob Rohr]

Chlorides are the usual suspect in stainless steel problems like that. Check the TDS and also the chloride levels if you can.

Seems like all the stainless tank and boiler manufacturers are adding water quality spec and caution on the tank and in the manuals.

Here is a spec from HTP form their stainless tanks.