oxygen

Duncan_2

Great explanation, Ken (it is Ken, isn't it?)as good as ever I've heard, simple and nicely done. Who cares if somebody yells? The fact is, there are systems out there that need help.

OK... Sodium molybdate for protective coating and DiPotassium Phosphate for pH, but what's the chemical that provides the SO2 or other oxygen scavenger? Is that also the DPP?

As far as NEW installations, even though treatment of water is an accepted DIN standard approach, a comparison occurred to me...

Having to constantly check water quality is like fixing a leak in a tire by constantly adding more air from time to time. The real fix is patching the leak (HX) or replacing the tire (ripping out the O2 permeable stuff and replacing with PEX). No offense intended - there are many ways to skin a cat - meow, ouch!

Of course, in large commercial systems with mega-dollar components, checking system water quality annually is a MUST, IMO.

Sounds to me like John T wants to avoid ripping walls out to replace piping. That leaves treatment or a heat exchanger as options.

P.S. I wouldn't mind if you emailed me with some info. Don't worry, I'm not competition - I'm outta the biz - just curious, always have been. I wouldn't mind meeting you sometime, you're in the Springs, aren't you?

John T

oxygen

I have a cast 225 boiler running primary/secondary with 11 in-floor radiant zones using circulators. Variable speed injection with outdoor reset and an indirect fire water heater. All the in-floor piping has O2 barrier. Some of the manifolds are connected with AQUAPEX (no O2 barrier). I am having a problem with rust in the system. I suspect the Aquapex is the problem. Can anyone recommend a chemical (Brand) to add to this system. I lost the injector pump a couple days ago. It was full of rust. Replacement of the Aquapex is not an option. Any help would be appreciated.

Terry

best bet

my best bet in past has been to isolate non barrier portion with a heat exchanger & NON ferrous material on non-barrier side of HE.

Oxy Perm is ongoing so chemical addition is not cure.

Terry.

Scott25

treatment

I would suggest using a treatment that included an oxygen scavenger. By maintaining a residual amount of scavenger the oxygen would "be eaten" as soon as it permiated the tube or any point of entry. Also a properly applied treatment program would protect the ferrous components as well as copper, brass and aluminum. It is also probably a lot cheaper that heat exchangers and piping changes. Email me and I can get you in touch with a company that has a product specifically for hydronic systems.

Scott

hr

Worked them both ways

HXs work but will require a second pump, air purger, expansion tank, relief, possibly low water cutoff of second fill system and backflow. Also you will lose some temperature and efficiencies through the HX. Non ferrous pumps and stuff get pricey.

Chemical treatment fixes other potential ailments. Corrosion, ph, scale build up, etc. It will need to be checked and boosted ocassionally depending on the rate of O2 diffusion. The cooler you can run the non barrier the less of an O2 problem you will create.

hot rod

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KCA_2

Chemicals


I know that I'll probably get yelled at for this but!

I don't use O2 barrier anyway. And yes! O2 does cause coorosion as well as other issues in a system but! What I do do (not the doggy stuff) is use chemicals and maintain the systems that we install on a yearly basis. They need to be maintained anyway so ....

Anyway.. An O2 scavanger works depending on the amount of O2 diffusing into a system. Without an O2 barrier to much O2 can diffuse so a scavanger isn't a good choice. I've checked it years ago when I first started using chemicals. SO2 goes to SO3 after combining with O2 so you can check remaining SO2. I did that on a daily, weekly basis to see O2 diffusion. SO! using a chemical like Sodium Molybdate coats the ferrus parts of the system. Maintaining a velocity under 4'/sec though is necessary (thats another story). Using DiPotasium Phosphate works with the pH and maintaining a pH of 8 or better (9+-) actually helps a coorosion issue. A chemict in your area could help you with the chemicals. I pay about $150 for a gallon jug of Molybdate and about $50 for DPP. There's more so if you're interested e-mail me..

:-) Kca

KCA_2

Hi Duncan!


I've been preaching chemicals for quite a while. A few weeks ago I had an oppertunity to go to Calgary, Canada to Heat-links shop and see what they have to offer. They are really a good organization.
The 2 day seminar talked of alot but one thing that I was proud of that they preached was the use of chemicals in a hydronic system. Relying to much on an EVOH barrier can actually be dangerous. Diffusion still takes place and O2 barriers actually can disolve in H2O
((Snow melts, Stadiums, green houses etc). Wirsbo says that a new heatpex they have has a extra coating on it to mitigate this problem.) (I have another posting here to see if anyone else knows about EVOH solubility but haven't recieved anything yet except from a gentleman fron Weil McClain.

Anyway.. Sodium Sulfite is an O2 scavanger and turns to Sodium Sulfate once it combines with an O2 molecule. It's OK but you do need alot to mitigate diffusion.
As far as constantly checking the water, I suppose that you could look at it that way but, we maintain systems anyway and once you know how much to put into a system then it's relitively easy to determine how much to keep in. The Reference book that is left in each mechanical room talks about chemicals and that they need to be checked (along with everything else) yearly.
LWCO's need to have the probe cleaned yearly or so..just as a for instance.

Sorry to hear that you're out of the Biz!! I'll e-mail you
and yeah! I'm in the springs.. You're in Divide?
:-) Kca

hr

I agree with

the chemical solution, also! I wonder how much protection the EVOH barriers REALLY provide. How can one tell looking at the tube whether the barrier process was complete! How much EVOH damage can a tube, or system, handle?

Do you have an EVOH barrier tester on your truck I have yet to find one! As we both know the system "breakdowns" occur years down the road generally.

I still prefer a professionly built inhibitor however. I need assurance it will protect, without attacking, all the systems components. The one I use now has a couple dozen ingrediants and has been lab tested, and built specfically for hydronic use. The EPA label means a lot also! Blending chemicals can be tricky business Sounds like you have done some homework, but be careful.

Checking fluids on a yearly basis is a good way to keep in touch with customers. It can be done to "fill in" at slow times. Sometimes it leads to additional sales, or other leads. It's great PR showing your customer you service goes beyond the initial install, I feel


hot rod

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John T

thank you

Thanks to everyone. Yes I do want to avoid ripping out walls and No a heat exchanger is not practical. An oxygen scavenger chemical is exactly what I'm looking for. I feel oxygen will be a problem even if I replace the non barrier stuff. Any recommendations on who to contact?

Kca

Try


A chemist. Look it up in the yellow pages. Or maybe a chemical wharehouse. Some of the wharehouses like to sell 55gallons at a time but check around. Where are you. I can check with my guy..

:-) Ken