I'm going to post up what Wood Doctor advises for boiler treatment!
What they were asvising before I had two of their stainless boilers corrode through on me!
And what they're advising now!
But before I do that ....
Eyes Wide Open!
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
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