OWB - Open Systems Corrosion Problems!

I am the not so proud owner of my second 2000 lbs stainless steel exterior wood furnace sold to me by Wood Doctor.

My original furnace developed perforations in it's belly causing it to loose all it's water in only it's second heating season. I managed to make it to spring by holding vigilance over ten or so pine plugs hammered into the holes to stop the leaks! :red:

I received a replacement stainless steel boiler that has now just barely made it threw it's third heating season this time developing perforations primarily along the belly weld lines! :sick:

So what can be done to reduce the corrosion problems in open systems? :question:

Well one thing I have done is introduce an anode into the piping on the back of my Wood Doctor hoping for the best!

A picture is worth a thousand words . . . see below!

A standard DHW anode is inside the black iron with a ground wire strapped on to ensure it's grounded (above is my spare anode).

Well, it should have help tremendously! My boiler is supposed to be high quality heavy gauge Stainless Steel after all! :-/

Perhaps on another product, it would have made a great difference! :zip:

Leaky :down:

leaddog said:

There are a lot of different grades of stainless and all have different properties. Some will even atract a magnet. They make the boilers out of a thinner guage also because of the cost. My neighbor has several that he picked up to scrap that are all stainless and they are full of holes. Looked like it was a cheap grade and wasn't uniform steel. Probably from a small mill in china.
leaddog

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Yes,

This is what I think must be going on - cheap 409 made somewhere where quality control is a joke and aloud into our country for the sake of saving a buck on materials!

On my system I also see evidence that seems to indicate to me that the stainless my have been improperly welded causing it to loose it's anti-corrosive properties along weld lines. This is where mine is perforated - along the weld lines (see picture)!

Leaky :-/

I'm going to post my boiler treatment recomendations from Wood Doctor as it appears they have completely changed their tune on this since my first two SS boilers developed leaks!

I'm interested to see what other OWB Dealer's are telling their clients to do as well!

Ok, here I'll post what I was originally told to do by Wood Doctor!

In my next response, you can see what they say to do after I have already had two boiler corrode through!

Leaky :-S

This is what they say now!

Leaky :-/

Here's some more interesting stuff!

Eyes Wide Open! :gulp:

Here is an very interesting blurb I just received from a friend!!

Can't say I know for sure if it is all correct, but it sure sounds feasible to me!!

How Wood Doctor can just sell customers an OWB and then just leave them in the dark about all this stuff, I do not know???

Well hey, they are the ones warrantying the durability of their products against corrosion among other things, so they're actually the ones on the hook to fix these leaking beast, or so you would think!!

My friend says the following in regard to my . . .

"Corroded Leaking FULLY WARRANTIED Heavy Gauge Stainless Steel WOOD DOCTOR Furnace"

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I would venture to suggest, that they may be using 406 stainless as it welds up good with normal steel panels. However, it also has the characteristic of creating galvanic cells within itself if it lays submerged in still brackish water (freshwater with higher then normal chloride levels).

Are you leaving your system full in the summer when not in use and have you tested water for chloride levels (salt). It could be that you are using system in the summer too, but you are not getting enough demand to keep water circulating enough. Whatever the case, it could be that there are pockets of still brackish water forming galvanic cells next to the stainless!

Unless you are regularly blowing down (draining boiler bottom liquid/sludge out under pressure) and topping up with new water you will over time have chloride build up to dangerous levels (levels high enough that the boiler water becomes an electrolyte and allows galvanic cells to form). Then away goes the iron in your stainless steel alloy and oops there is a hole. This will occur mostly near the bottom of your boiler where salt concentrations will be highest!

Monitoring PH levels is good, but PH only helps reduce corrosion by keeping water slightly alkaline. Unfortunately, even alkaline water becomes an electrolyte if chloride (salt) PPM get high enough.

Desired level of chlorides should be around 15-25 PPM, but practically you would probably have difficulty keeping it between 50-75 PPM.

You need to test water with silver nitrate chloride test kit to get PPM. You will likely find that you will need to start draining water regularly to keep chloride levels down. You are shooting yourself in the foot by running the same old soup in system forever, or in this case until it cuts it's own drain holes and runs out on the ground.

In these open systems, boiler water will only continue to build in chloride content as pure water is boiled off (concentrating the soup) and then new water containing even minute levels of salts is added! That is why boiler water neutrality is controlled by controlling it's dissolved solids (salts etc.).

You don't have to re-invent the wheel here, just trust the accepted methodology. The idea is to reduce the capability of your water to conduct current, thereby reducing corrosion caused by galvanic cells (dissimilar metal molecules next to each other in your stainless steel alloy mix). Again this is relative, but basically dissimilar metals that are fused together in an alloy create there own electric circuit (or electron flow), this is how thermal couples work. Anyway, in a mixture (an alloy) an electrolyte is also needed to allow this electron flow to occur (like a battery). Reduce the strength of the electrolyte and you will reduce electron flow and thereby reduce corrosion!
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Please, someone with some additional knowledge about this subject offer us some more insight!

Are there OWB dealers out there telling there customers they need to flush their furnaces on some kind of regular basis, or what?

Did you all notice this particular sentence . . . "You don't have to re-invent the wheel here, just trust the accepted methodology" >:-(

I'm putting a pic here showing those holes in my Wood Doctor heavy gauge stainless steel furnace . . .

Leaky :sick:

What a farce . . . yours rusted from the outside-in (inside-out to me would be from the water jacket, out!) and they are denying warranty. :red:

Does Wood Doctor say anywhere in the literature they provided to you that there is a limit on the length of pipe you can install and that this may happen if you install too long a piece and they will there-by void your warranty?

Did they convince you to ship your entire boiler to their factory for examination at your expense and then pull this excuse to void your warranty out of their hat?

So, "Now We Know!!", Wood Doctor's boiler plate lasts about 6 heating seasons before corroding through and leaking all over the ground and Heavy Duty Stainless Steel can corrode through in less than 3 heating seasons!!

Isn't that Wood Doctor product just the cat's meow!

So to add to the confusion that Wood Doctor seems to wallow in . . . is your boiler "Heavy Duty Full Boiler Plate" or did they manage to slip you something they might now describe as "Light Duty Half Boiler Plate" that you didn't think you had bought from them in the first place?

Wood Doctor is telling me now, that I originally bought a Light Duty Stainless Steel Global Hydronics boiler from them. Funny, how I never heard any of these terms until well after the fact! I know what I bought from them, "A Heavy Duty Stainless Steel Wood Doctor Furnace!"

It's like they're trying to say, "You bought our cheap product and got what you paid for! What did you expect, Dah!" >:-(


Leaky :down:

Wood Doctor didn't even come look!

No curiosity on their part, ahy! :roll:

They already know what the problem is - don't they!

Post some pictures when you get some - they're worth 1000 words you know! ;-)


Leaky :down:

Hey,

I have heard via the grape vine that Wood Doctor maybe soon be sending a certified welder to my home to repair my leaking beastie! 8-/

If this actually happens, the words "On Site" in my warranty will actually mean, "On Site!" .

I hope to be impressed by the work that is done to repair the many leaks and cracks in my Wood Doctor boiler and will be sure to post a number of pictures here to document the work for all to see!

Perhaps next heating season will be a "leak-free" one!

Leaky

AdkMike said:

"I’m wondering why you want to flush (and treat) your system? If it’s been in operation for a season, and properly treated to begin with, all that should be required is periodic monitoring (especially an open system) to make sure that pH and O2 control chemicals are correct."

You are probably correct. But, call me naive, I'm simply following the end-of-heating-season guidance as documented in my Woodmaster paperwork. I am assuming that if not followed correctly, certain parts of my warranty will be voided.

Mike

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Hey,

So there are warranties out there requiring that the system be flushed Yearly!

Perhaps the manufacturers are getting wise to salt build-up! ;-)

Wood Doctor sends a Welder!

See my post under Outdoor Wood Boilers Review . . .

Leaky

PS - I think I have found a test kit that I can now monitor salt concentration with! Also, salt seems to concentrate at the bottom of my boiler and I now have a ball valve to allow me to drain off water from the bottom and add fresh to the top if I detect a build up of salt!

Wish me luck! :roll: