Oxygen dissociation

 
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Lightning
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Post by Lightning » Wed. Dec. 30, 2020 3:51 pm

McGiever wrote:
Wed. Dec. 30, 2020 2:22 pm
BTW: Even with burning DRY coal there will still be enough moisture available to condense at too low of temperature
Right, since there are hydrocarbon components in coal also. Those hydrocarbons oxidize into water and carbon dioxide along with other trace compounds.

 
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Post by snuffy » Wed. Dec. 30, 2020 7:24 pm

lsayre wrote:
Wed. Dec. 30, 2020 11:43 am
All plastics are gas permeable to some measure, including oxygen barrier plastics. Copper is not gas permeable.

If a plastic existed which did not permit the inflow of oxygen, beer intended for longer term storage would be sold in plastic bottles. No such bottle exists, so its cans or glass bottles. The plastic stadium beer bottles are intended for nominally immediate consumption. Even the properly sealed 'crown' cap of a glass beer bottle is detrimentally gas permeable. That leaves only cans for truly long term stability.
Isayre's post is what makes me suspect the pex as it is also exposed to daylight as well. Rob's point is well taken so I think I will collect a sample and have it tested then we'll answer this assumption for my part anyway. Interesting discussion on dissociation as I once lowered the water temp hi/lo one summer and my plumber told me not to but never said why. When I have an answer I'll repost. Thanks!

 
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Post by lsayre » Wed. Dec. 30, 2020 7:46 pm

DO (dissolved oxygen) meters are dirt cheap these days.


 
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dbsuz05
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Post by dbsuz05 » Wed. Dec. 30, 2020 9:15 pm

For years I had bubbles in my system. Could hear them bubbling through the lines and radiators. Then I bought a webstone air eliminater. There’s some bubbles in the system from not running all summer and then they just disappear and it’s quiet once temp stays up. So I figure I did my best to save the system.
You may get a really cold night that your boiler gets up over 150 and you’ll hear some burbles. Heck mine sometimes hisses when it gets up to 170-190! Been doing it for 10 years no issues yet!

 
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Post by Chancey P. » Fri. Feb. 25, 2022 11:29 pm

So now that I have a control valve in place connected to a thermostat It will stop all flow when the house reaches temp. So even if I never hit over 140 while running. sometimes during the day usually in the afternoon the valve closes and the boiler will slowly creep up to 180 and then the override kicks on even if the boiler is set at 100 (on the really mild days). I wonder if that is enough to keep this issue at bay. It doesn't happen everyday, but I'd say few times a week average.

 
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Post by coalder » Sat. Feb. 26, 2022 8:03 am

dbsuz05 wrote:
Wed. Dec. 30, 2020 9:15 pm
For years I had bubbles in my system. Could hear them bubbling through the lines and radiators. Then I bought a webstone air eliminater. There’s some bubbles in the system from not running all summer and then they just disappear and it’s quiet once temp stays up. So I figure I did my best to save the system.
You may get a really cold night that your boiler gets up over 150 and you’ll hear some burbles. Heck mine sometimes hisses when it gets up to 170-190! Been doing it for 10 years no issues yet!
FWIW, had a similar issue with my hand fed boiler. Was constantly plagued with air in the system. Would constantly sound like a babbling brook as the calculator between the two boilers ran. Couldn't figure out where the air was coming from & my vents could,'t vacate the air fast enough.

So, this past summer I replaced the gaskets on both circulators & solved the problem. The gasket on the main circulator was about 25 yrs old, & severely disintegrated; however showed no signs of leakage. But, when it kicked on, it apparently was able to suck in air from around the gasket & cause the problem. Now the system runs in absolute silence.

Any hissing or burbling in your system indicates air & a closer look might be warranted.

Jim


 
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Lightning
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Post by Lightning » Sun. Feb. 27, 2022 2:27 pm

As far as dissolved oxygen is concerned in the boiler water, there is a significant correlation to temperature and parts per million as demonstrated in the graph I found. Maybe this is helpful. I would imagine that over time its all forced out and can not reenter if oxygen barrier piping is used in a closed system. Just my best guess..

I would also imagine that there is a lot of nitrogen gas dissolved in a freshly filled boiler also, which is also driven out over time and scooped out.

So based on this, maybe its wise to run the boiler water up to 200+ degrees once just to get most of the dissolved air out?
Maybe, maybe not.. It's a little out of my pay scale :lol:

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Post by Scout80 » Tue. Apr. 05, 2022 11:00 pm

:clap: I’m gona like this forum. :clap:

 
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Post by OTR » Thu. Sep. 15, 2022 3:55 pm

coaledsweat wrote:
Mon. Dec. 28, 2020 9:14 pm
The water left in all summer will be oxygen rich if it isn't up to operating temperature. As soon as it cools down after you shut it down it will draw oxygen into the water. There is no way to keep it out. Your system may be sealed so it doesn't leak water but you can't keep oxygen out of it.
Where would the oxygen come from in a sealed system? Any air in the system should have been removed from bleeding, whether manual or automatic, right?

 
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Post by coaledsweat » Thu. Sep. 15, 2022 5:23 pm

No system is totally sealed. Oxygen will diffuse into the water slowly and relentlessly.

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