Changing out the water in your OWB?

[NSMaple1]

Garn has been making non-pressurized vented boilers of the gassifying nature for decades. They recommed annual water testing, and treatment if needed, but not water changes. The reputation is second to none.

 

[raptor]

Well said! C 5rulz

 

[CTYank]

I cant comment on stainless steel with certainty, it seems that stainless has its own host of enemy's , mostly depending on the type (purity) of it. Since I had already determined what I was going to purchase I did not research it thoroughly Would seem logical that treatment of the water would be necessary to me. I'd very much like to here some comments from knowledgeable sources. NSmaple1 commented that rain water is not distilled water of which he is correct. Although the process is similar rain water becomes contaminated altering it's characteristic for our purposes. PH of rain water is hard to manage as anyone with a pool will tell you. Water, specifically distilled water is a poor conductor of heat and a poor very poor conductor of electricity. Good because it discourages electrolysis but bad because transfers heat poorly.

No OWB here, but ...
Water is a poor heat conductor, period. Meaning conductor of heat through the water. That has zero to do with heat conduction at the metal-to-water interface. Tremendous difference. Navy steam boilers use triple (or more) distilled water, de-aerated as possible, and they sure seemed to transfer heat from the tubes to the water readily. Ditto for superheating the steam.
Dissolved oxygen in feed water is a problem. Oxygen that has reacted with hydrogen to become water, went through a reaction so exothermic that it is inert as far as reacting with water-sides of heat exchangers.

 

[raptor]

Thanks for input! That's one reason I mentioned earlier that pressured systems behave differently.

 

[Dogsout]

No OWB here, but ...
Water is a poor heat conductor, period. Meaning conductor of heat through the water. That has zero to do with heat conduction at the metal-to-water interface. Tremendous difference. Navy steam boilers use triple (or more) distilled water, de-aerated as possible, and they sure seemed to transfer heat from the tubes to the water readily. Ditto for superheating the steam.
Dissolved oxygen in feed water is a problem. Oxygen that has reacted with hydrogen to become water, went through a reaction so exothermic that it is inert as far as reacting with water-sides of heat exchangers.

I manage our little 200 PSI boiler at work and do most of the testing. Your biggest problems with boilers is scaling and corrosion. This is why there is so much pretreatment to the water before it enters the boiler. We need to keep in mind that there is a big difference between open and closed (pressurized) systems. IMO if you want to pick one thing to concentrate on for an OWB it would be the PH. This is something that is easily tested for and easy to keep under control. I don't change the water in my OWB but I do check it often and keep it in check. Boiler water is reused in the form of condensate for the most part (Until blown down out of the system) in much harsher conditions then your little OWB. Finally I am having trouble wrapping my brain around triple distilled water. Our system runs on soft water through the RO one time and treat it down to 10 TDS and a conductivity of around 600. Don't see a whole lot of improvement to be had by running it two more times.

 

[c5rulz]

No OWB here, but ...
Water is a poor heat conductor, period. Meaning conductor of heat through the water. That has zero to do with heat conduction at the metal-to-water interface. Tremendous difference. Navy steam boilers use triple (or more) distilled water, de-aerated as possible, and they sure seemed to transfer heat from the tubes to the water readily. Ditto for superheating the steam.
Dissolved oxygen in feed water is a problem. Oxygen that has reacted with hydrogen to become water, went through a reaction so exothermic that it is inert as far as reacting with water-sides of heat exchangers.

I would imagine that the extreme emphasis on triple distilled water is dissolved solids are mighty bad on turbine applications.

 

[hammerhead 5410]

I like where this thread has gone!opcorn:

 

[c5rulz]

I like where this thread has gone!opcorn:

Are you implying that the input of us who know nothing about the topic at hand having opinions?

I make it a point of not allowing my steamship mouth to over run my rowboat A$$.