Pex tubing
- Thread starter Rnbuck01
- Start date
Bondo
Well-known member
Ayuh,.... The heat limits don't change,...
Pex with an oxygen barrier stops all the other plumbin' parts from corrodin' away,....
Use the right stuff, it ain't that bigga difference in price,....
Pex with an oxygen barrier stops all the other plumbin' parts from corrodin' away,....
Use the right stuff, it ain't that bigga difference in price,....
Gidge
Well-known member
+1 ---Copper over pex any day (...and no BPA).
Gidge
Well-known member
I used pex for baseboard heating in my previous home and I noticed corrosion after about 2-3 years around the 90⁰ barb elbows. I did use glycol anti-freeze in the boiler, and this may have caused the corrosion. Live and learn !
ETA: Copper will last for decades w/o issues.
ETA: Copper will last for decades w/o issues.
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Bondo
Well-known member
Ayuh,... The problem is, What ya Don't see,....
Bondo
Well-known member
Ayuh,.... The antifreeze will only cost ya 'bout 4 times what just buyin' the right tubin' will cost,.....
WTF is the problem with just buyin' the Proper tubin',..??..?..??..??
If ya wanta reinvent the wheel,...
Plumb the whole thing with ole junk garden hoses,.....
WTF is the problem with just buyin' the Proper tubin',..??..?..??..??
If ya wanta reinvent the wheel,...
Plumb the whole thing with ole junk garden hoses,.....
rlitman
Well-known member
What he said!
Unless you've got a heating system that can deal with oxygenated water (all stainless and bronze), you will see an awful failure in short order, and the corrosion will happen from the inside out, so it will fail irreparably and without warning. Antifreeze is not the answer for corrosion protection.
Garden hoses. LOL! Good idea.
sands35
Well-known member
The elbows aren't the problem (can get plastic connectors), its the heat exchange in the water heater and the pump bodies that will be the problem.
Not sure, but something like water wetter will have rust inhibitors. But this is a chemistry problem and I'm not a chemist.
Likely, you should test the PH of the system every year and be prepared to replace the glycol more often. Probably best to stick with hydronic glycol. I would suspect that it has inhibitors in it to control corrosion.
Not sure, but something like water wetter will have rust inhibitors. But this is a chemistry problem and I'm not a chemist.
Likely, you should test the PH of the system every year and be prepared to replace the glycol more often. Probably best to stick with hydronic glycol. I would suspect that it has inhibitors in it to control corrosion.
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rlitman
Well-known member
Ouch! I kind of had that feeling, the way you posed your question.
Well, for starters, you can use a bronze or stainless pump. Use no galvanized or black iron pipes, and use a stainless heat exchanger, and then don't worry about the missing oxygen barrier.
What's your planned heat source? There are plenty of condensing boilers that have stainless heat exchangers. Or are you doing something more exotic?
As for temperature, the oxygen barrier in he-pex has nothing to do with the temperature the PEX is rated to.
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Bondo
Well-known member
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rlitman
Well-known member
A water heater is glass lined and has an anode. It's meant to be ok with domestic water (for the nominal life of the heater). So, if everything else in your setup is ok with domestic water, you're not totally screwed corrosion wise.
dfiler2
Well-known member
You can also protect the system with rust inhibitors, much cheaper than anti-freeze and simple to do. You don't have to use stainless steel HE's or bronze pumps. Lots of systems out there without oxygen barrier PEX and they can be well protected. If you want to send me a PM I can help you out.
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BadgerBoilerMN
Well-known member
Nonsense.
Inhibitors have a limited life.
In the long run a relatively inexpensive SS plate heat exchanger will allow you to use standard components on the expensive heat source side of the system and stainless/bronze components on the non-barrier PEX side with a potable water expansion tank and relief valve.
It pays to get some design help and get the proper specifications before your pour the concrete.
Anti-freeze, made for hydronic heating, includes the proper inhibitor, which inhibits the growth of anerobic bacteria and "rust", but must be maintained for freeze protection and corrosion control. Old anti-freeze will go sour and become acidic, attacking ferrous and non-ferrous metals, clogging the system components.
Inhibitors have a limited life.
In the long run a relatively inexpensive SS plate heat exchanger will allow you to use standard components on the expensive heat source side of the system and stainless/bronze components on the non-barrier PEX side with a potable water expansion tank and relief valve.
It pays to get some design help and get the proper specifications before your pour the concrete.
Anti-freeze, made for hydronic heating, includes the proper inhibitor, which inhibits the growth of anerobic bacteria and "rust", but must be maintained for freeze protection and corrosion control. Old anti-freeze will go sour and become acidic, attacking ferrous and non-ferrous metals, clogging the system components.
dfiler2
Well-known member
Just curious what you are calling nonsense?
BadgerBoilerMN
Well-known member
Chemistry must be maintained.
The German standard for oxygen diffusion is DIN4726 but even this approved barrier standard requires an annual oxygen diffusion test.
I looked at a home builder's own "DIY radiant" job yesterday. While building his own house the builder ran down to the nearest Big Box store to buy his PEX. He neglected to buy the oxygen barrier PEX and also go stuck on the heat source So the 2500 sq.ft basement is cold, -13°F this morning in Eden Prairie, MN, and I was called in to sort it out.
First. Oxygen is not the enemy; ferrous metal are. It is when the iron in the commonly used hydronic components oxidize from the oxygen naturally occurring in water that the problem arises. Once depleted, as a result of reacting with the ferrous metal--pump housings, expansion tank, etc.--a old style, all-metal system would normally work fine.
However, when you have a regular supply of oxygen migrating through the non-barrier PEX, the result can fill the system components up and even block flow through HX or the close spaces of valves. The higher the operating temperature, the higher the oxygen diffusion rate. Many radiant slab applications and snow melting system will suffer a very low diffusion rate. To the point that heat exchangers and even non-ferrous components are optional. In these low temperature applications the proper dose of inhibitor, as d suggests, may be all you need. But, you must maintain any heat transfer fluid for long term reliable operation, just as you do in your vehicles.
Generally, total system operating temperatures below 104°F will be safe, something we learned the hard way back in the 90's when we used non-barrier polybutylene for all of our radiant work. This excludes the use of mixed temperature systems e.g. cast iron boilers, outdoor boilers and mixing arrangements that allow any portion of the PEX to go above body temperature.
The answer is; separate the source of oxygen, typically with a plate heat exchanger or to design the system with non-ferrous metal components e.g. SS pumps and potable water expansion tanks.
This is done regularly on commercial applications where the extra 10 cents per lineal foot could add thousands to the PEX installation.
All hydronics systems should be flushed, cleaned, flushed again and treated with an appropriate corrosion inhibitor. Know what, how and when is the trick.
No disrespect to d.
The German standard for oxygen diffusion is DIN4726 but even this approved barrier standard requires an annual oxygen diffusion test.
I looked at a home builder's own "DIY radiant" job yesterday. While building his own house the builder ran down to the nearest Big Box store to buy his PEX. He neglected to buy the oxygen barrier PEX and also go stuck on the heat source So the 2500 sq.ft basement is cold, -13°F this morning in Eden Prairie, MN, and I was called in to sort it out.
First. Oxygen is not the enemy; ferrous metal are. It is when the iron in the commonly used hydronic components oxidize from the oxygen naturally occurring in water that the problem arises. Once depleted, as a result of reacting with the ferrous metal--pump housings, expansion tank, etc.--a old style, all-metal system would normally work fine.
However, when you have a regular supply of oxygen migrating through the non-barrier PEX, the result can fill the system components up and even block flow through HX or the close spaces of valves. The higher the operating temperature, the higher the oxygen diffusion rate. Many radiant slab applications and snow melting system will suffer a very low diffusion rate. To the point that heat exchangers and even non-ferrous components are optional. In these low temperature applications the proper dose of inhibitor, as d suggests, may be all you need. But, you must maintain any heat transfer fluid for long term reliable operation, just as you do in your vehicles.
Generally, total system operating temperatures below 104°F will be safe, something we learned the hard way back in the 90's when we used non-barrier polybutylene for all of our radiant work. This excludes the use of mixed temperature systems e.g. cast iron boilers, outdoor boilers and mixing arrangements that allow any portion of the PEX to go above body temperature.
The answer is; separate the source of oxygen, typically with a plate heat exchanger or to design the system with non-ferrous metal components e.g. SS pumps and potable water expansion tanks.
This is done regularly on commercial applications where the extra 10 cents per lineal foot could add thousands to the PEX installation.
All hydronics systems should be flushed, cleaned, flushed again and treated with an appropriate corrosion inhibitor. Know what, how and when is the trick.
No disrespect to d.
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dfiler2
Well-known member
I don't disagree with anything you've said here, it appeared you were saying that my post was "nonsense". We deal with these systems everyday , in a pressurized system using oxygen barrier PEX is very important. Water over 170 has almost no free oxygen to cause corrosion, however, once the system is cooled down the oxygen will be pulled back into the water and it will be pulled through the tubing if there is no barrier.
Our systems are different in that we are non-pressurized and for a good reason. When you are using NG, LP or fuel oil or electric it's fairly easy to shut off the fuel source if there is a problem. When using wood as a fuel source it's difficult to shut off the fuel source so we run them without pressure to keep people from creating dangerous situations. We sell only oxygen barrier PEX because the system may be changed to a different heat source in the future.
Because of the large water volumes in our systems, using antifreeze can be cost prohibitive. We have spent the last 25+ years perfecting the protection of our steel systems, and because these units are generally operated by homeowners it's important to give them the proper tools to "maintain the chemistry".
There is often bad information given out on this site and I usually read on and hope the OP gets their problem solved. What bothered me about this thread was there were several comments that basically told the OP they were screwed when in fact there were several ways to make sure his system lasted for many years. You have one way and I have another. I would have set this customer up with the inhibitor and a test kit that would protect his system from corrosion.
We have put a lot of time and energy into protecting non-pressurized systems from corrosion without using an antifreeze and I'm guessing you have not put in any.
We are fairly close to each other and there is ice on the lake, I would invite you to stop by the plant any time and I will give you a tour and show you exactly what we are about.
Our systems are different in that we are non-pressurized and for a good reason. When you are using NG, LP or fuel oil or electric it's fairly easy to shut off the fuel source if there is a problem. When using wood as a fuel source it's difficult to shut off the fuel source so we run them without pressure to keep people from creating dangerous situations. We sell only oxygen barrier PEX because the system may be changed to a different heat source in the future.
Because of the large water volumes in our systems, using antifreeze can be cost prohibitive. We have spent the last 25+ years perfecting the protection of our steel systems, and because these units are generally operated by homeowners it's important to give them the proper tools to "maintain the chemistry".
There is often bad information given out on this site and I usually read on and hope the OP gets their problem solved. What bothered me about this thread was there were several comments that basically told the OP they were screwed when in fact there were several ways to make sure his system lasted for many years. You have one way and I have another. I would have set this customer up with the inhibitor and a test kit that would protect his system from corrosion.
We have put a lot of time and energy into protecting non-pressurized systems from corrosion without using an antifreeze and I'm guessing you have not put in any.
We are fairly close to each other and there is ice on the lake, I would invite you to stop by the plant any time and I will give you a tour and show you exactly what we are about.
Ran pex in radiant flooring for years with no antifreeze or water wetter for a little over 10 years now with temps of over 140-150f. Zero problems. I dont understand the issues a lot of people have with pex. I love the stuff and will never go back to copper ever again.
dfiler2
Well-known member
This isn't an issue with PEX in general, it's an issue with non-barrier PEX used in a heating system. PEX is a great product. If what you have is a pressurized system and you have not been adding water to the system you may be fine for many more years.
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BadgerBoilerMN
Well-known member
I design hydronic systems for a living, using all sorts of solid fuel, and duel-fuel boilers with and without anti-freeze.
Wood boiler manufacturers use a heavy dose of inhibitor and coach their clients to do the minimum chemistry tests to avoid building more expensive ASME vessels, thus the more marketable "open" system. Open to the atmosphere and the detrimental effects the oxygen in free air, since the most common wood boiler material is still boiler plate, oxygen is bad...
I isolate my wood boilers and their chemistry from my, typically expensive, hydronic components and backup gas boilers, with plate heat exchangers.
If you didn't use barrier PEX with your wood boilers you would be selling a lot more inhibitor I think.
As John Siegenthaler likes to say; "The only good thing about anti-freeze is that it doesn't freeze.
I would like to tour your plant on my way to visit the Grand-kids in Fargo. I might even be in the market for a new boiler.
Wood boiler manufacturers use a heavy dose of inhibitor and coach their clients to do the minimum chemistry tests to avoid building more expensive ASME vessels, thus the more marketable "open" system. Open to the atmosphere and the detrimental effects the oxygen in free air, since the most common wood boiler material is still boiler plate, oxygen is bad...
I isolate my wood boilers and their chemistry from my, typically expensive, hydronic components and backup gas boilers, with plate heat exchangers.
If you didn't use barrier PEX with your wood boilers you would be selling a lot more inhibitor I think.
As John Siegenthaler likes to say; "The only good thing about anti-freeze is that it doesn't freeze.
I would like to tour your plant on my way to visit the Grand-kids in Fargo. I might even be in the market for a new boiler
.
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dfiler2
Well-known member
Good to hear, and just for the record we manufactured "H" stamped gas boilers for a number of years so I am very familiar with the ASME vessels.
This statement "Wood boiler manufacturers use a heavy dose of inhibitor and coach their clients to do the minimum chemistry tests to avoid building more expensive ASME vessels..." is very inaccurate at best, for us anyway.
This statement "Wood boiler manufacturers use a heavy dose of inhibitor and coach their clients to do the minimum chemistry tests to avoid building more expensive ASME vessels..." is very inaccurate at best, for us anyway.
Plump
Well-known member
How does this affect my existing boiler/radiator system as far as corrosion goes? I was planning on oxygen-barrier pex, but all the other parts of the existing system are iron, galvanized, etc.
BadgerBoilerMN
Well-known member
I mean to say; if you pressurized your systems you would be in a different insurance bracket. I too used to manufacture "H" stamp boilers.
You would have to charge like those European guys and the country folk would be very unhappy. They can hardly swallow "gasification"...
BadgerBoilerMN
Well-known member
Corrosion is a result of aggressive water. Source of oxygen keep the process of rust going until there is no oxygen or no ferrous metal to rust. Oxygen molecules can't migrate through steel, iron, copper or any of the common metal components of a common hydronic system.
It is the surface area of the PEX tubing that really presents the problem. Without an effective oxygen barrier ferrous metal component corrosion is certainty sans aggressive chemistry.
Bondo
Well-known member
Ayuh,... You'll be just Fine with barrier pex,....
BadgerBoilerMN
Well-known member
By the way. Galvanized pipe is not compatible with any heat transfer anti-freeze or propane...
Just ask Bondo!!
Just ask Bondo!!
The correct answer is you cannot. Why would you even consider non-oxygen barrier pex. Fools errand.
BadgerBoilerMN
Well-known member
It happens. Many mistake one for the other or buy from the Big Box without talking to one of their "knowledgeable" sales associates.
Many commercial building and snow melting systems are designed and installed by professionals.
Low temperature radiant floor installation will migrate little oxygen since the main function is driven by temperature. It is not for the amateur but can be done. With stainless components, supply water temperature below body temperature are generally acceptable. Good chemistry, as dfiler says is good business.
DIY radiant floor folks should spend a little more for the barrier PEX as Deke suggests.
Many commercial building and snow melting systems are designed and installed by professionals.
Low temperature radiant floor installation will migrate little oxygen since the main function is driven by temperature. It is not for the amateur but can be done. With stainless components, supply water temperature below body temperature are generally acceptable. Good chemistry, as dfiler says is good business.
DIY radiant floor folks should spend a little more for the barrier PEX as Deke suggests.
Kaizen
Well-known member
Great information everyone. Very informative. One question - the barrier is supposed to stop oxygen from infiltrating the pex and getting into the boiler correct? wouldn't pex that is concrete encased have a far lower number of oxygen molecules that it contacts? I understand in an underfloor open to air situation it would be 100 percent contact.
BadgerBoilerMN
Well-known member
Nice try, but no such luck. Concrete is vapor and gas permeable.
1969
Well-known member
Watching........
Plump
Well-known member
You guys are the best! Thanks!