Use of PEX for Basboard Heat Plumbing

[Lloyd]

WGB:

  The boiler will  be the only steel/iron in the system, and I wrestled with how to keep it from rusting away - filling the system with antifreeze is prohibitively expensive since 50:50 would require something like 625 gallons of antifreeze!!!  Sorta out of my budget bracket!  I was thinking to use something like hot water heater zincs as sacrificail anodes to keep the boiler from rusting away before my very eyes!!!

Regardz,

Wayne Stayton

Wayne,

Either be succinct or figger out a way to break it down in to manageable set of issues... Other wise I think you can't see the trees for the forest.

The issue with PEX and IRON...is, pex's ability to absorb oxygen, which is what cause the iron to rust from the inside out..

Sacrificail anodes will do nothing to keep the boiler from rusting out...they stop ecltrolysis...NOT RUST...they are 2 different things...both just happen to eat metal.

Barrier Pex(also called AlumiPex) is the only PEX(Aqua PEX won't work) that can be used in a black iron system, or any system that contains IRON.

Lloyd

[WGB]

WGB:

  The boiler will  be the only steel/iron in the system, and I wrestled with how to keep it from rusting away - filling the system with antifreeze is prohibitively expensive since 50:50 would require something like 625 gallons of antifreeze!!!  Sorta out of my budget bracket!  I was thinking to use something like hot water heater zincs as sacrificail anodes to keep the boiler from rusting away before my very eyes!!!

Regardz,

Wayne Stayton

Wayne,

Either be succinct or figger out a way to break it down in to manageable set of issues... Other wise I think you can't see the trees for the forest.

The issue with PEX and IRON...is, pex's ability to absorb oxygen, which is what cause the iron to rust from the inside out..

Sacrificail anodes will do nothing to keep the boiler from rusting out...they stop ecltrolysis...NOT RUST...they are 2 different things...both just happen to eat metal.

Barrier Pex(also called AlumiPex) is the only PEX(Aqua PEX won't work) that can be used in a black iron system, or any system that contains IRON.

Lloyd

This is getting complicated.
Most open systems with steel or wood boilers mantain water treatment that controls rust.
AlumiPex is Barrier pex, but there are 3 other types of oxy barrier pipe Pex A,B,and,C.
This is just me, but if I'm going to all the work of putting a hot water heat system in, I spend a little more and use oxy barrier pipe no matter what. If you do that you can change anything in the rest of the system later and not have to worry about it!
If you want I could try and help on the phone.
I do have all the Wirsbo, Viega, and other heat loss heat gain software.

[Tom Reed]

My system is open with an anode too. Guess that won't work. I also bought some soluble oil to address the rust issue, but haven't had the nerve to put some unknown mix through the PEX and cause it to melt. 

[Lloyd]

The simple solution,

If you don't want to use barrier pex(what ever name brand), then put a heat-ex(s) between the boiler/engines, and run glycol on the boiler/engine side and managed water on the heat sink side.

Lloyd

[WStayton]

Hi, All!

  Well, I guess yhou have convinced me that I need to use barrier PEX if I'm going to use PEX, which means that I have to unsolder the fittings on the baseboard units and solder on some new ones.

  It would see to me that I should use compression fittings for the PEX, since they don't require any sort of specialized tooling to install.  They are twice as much in cost as the special fittings for PEX, but even the rental of tooling would quickly eat up the differance in cost, especially since I'm not the type to lay out everything and then do all the crimping/squeezing in one afternoon but rather do things as I come along and scatter it over several days/weeks.

  Other than the fact that some PEX is certified for use with potable water and some isn't, is there any other differance that I should be looking at for BARRIER PEX???

  I do have to also plumb in a bathroom and replumb, with hot water, a kitchenette/dishwasher, so I'm thinking that I will just use the same PEX for everything and keep my materials selection simple .

Lloyd:

  I take issue with your statement that rust and alectrolysis are two differnet things.  In both cases the iron is oxidized to an oxide by a chemical process that IS inhibited by placing a more reactive metal in direct contact with the iron.  The real issue is if you can get the anodes installed in a sufficiently distributed pattern to protect all of the iron surface in something like a boiler.  If you can get to the intersticies of the boiler, which you can't, to place an anode for every couple of square feet of surface area, I don't care what type of corrosion you subject it to, the sacrificial anode will give itself up to oxidation and protect the iron.

   Since the best that I can hope for is to "sort-of" protect the boiler by putting anodes where I can get to the iron surface, I think that I will have to use barrier PEX.

  I toyed with the idea of running the output from the iron furnace through yet another set of heat exchangers, but there is a diminishment of heat transfer every time you place another exchanger in the loop and I THINK that I need all of the heat exchange that I can get, since wood fired boiler's are known to have variable heating cycles tied to firing of the boiler, so I don't think that it is worth the effort to try it and see if it will work.

About "succintness":

  When somebody asks me a legitimate question like "How does a nuclear submarine work?"  I just can not bring myself to answer with a short "Good!" and let it go - I think if they asked the question, they really want to know, and I should answer as fully and completely as I can.  Since I am 64 years old, it seems unlikely that I can retrain out this response form my repetoir!!!  Sorry, what you see, is what you get!  If it really bothers you, you can solve the problem by only reading as far as my id and then skipping to the next response!

  Thanx all, for the inpuit - you have narrowed things down for me!

Regardz,

Wayne Stayton

[Lloyd]

Hi, All!

  Well, I guess yhou have convinced me that I need to use barrier PEX if I'm going to use PEX, which means that I have to unsolder the fittings on the baseboard units and solder on some new ones.

  It would see to me that I should use compression fittings for the PEX, since they don't require any sort of specialized tooling to install.  They are twice as much in cost as the special fittings for PEX, but even the rental of tooling would quickly eat up the differance in cost, especially since I'm not the type to lay out everything and then do all the crimping/squeezing in one afternoon but rather do things as I come along and scatter it over several days/weeks.
Wayne Stayton

Google "pex law suit" you'll find most are related to leaking joints, from said use of compression fittings. Most plumbers I know that have a pot to p*ss, won't use compression fittings bc of the liability.

  Other than the fact that some PEX is certified for use with potable water and some isn't, is there any other differance that I should be looking at for BARRIER PEX???

  I do have to also plumb in a bathroom and replumb, with hot water, a kitchenette/dishwasher, so I'm thinking that I will just use the same PEX for everything and keep my materials selection simple .

Regardz,

Wayne Stayton

Well if you use an FDA pex for all then you risk all of your investment in corrosion loss to the boiler/engine/iron....It'll be cheaper to install, but in the long run it''ll cost you some IRON.

If you use all barrier pex, including for domestic water, then you'll pay abuo a third again as much for the domestic supply, and it might not be FDA appoved, so you have factor in the loss of life.

Lloyd:

  I take issue with your statement that rust and alectrolysis are two differnet things.  In both cases the iron is oxidized to an oxide by a chemical process that IS inhibited by placing a more reactive metal in direct contact with the iron.  The real issue is if you can get the anodes installed in a sufficiently distributed pattern to protect all of the iron surface in something like a boiler.  If you can get to the intersticies of the boiler, which you can't, to place an anode for every couple of square feet of surface area, I don't care what type of corrosion you subject it to, the sacrificial anode will give itself up to oxidation and protect the iron.

Regardz,

Wayne Stayton

Wayne,

You can take issue all you want but that won't change science. "Metal Erosion" is a catch all term, but the science says there are many forms of erosion. Such as galvanic, stray current, cavitation, oxidization, ionization...but a cure that works for one ....WON"T work for the other. Certainly not anodic protection, in lieu of oxidization protection.

I can take you to boat yard after boat yard that has old fishing boats, that all have iron, not bronze for under water metals. These metals are protected, by zincs for stray current/galvanic corrosion, when the boat hits dry land for the last time the metal are all intact, by year 4 the metals are rusting so bad they boil the paint, by year 10 the metals look like a form of swiss cheese/surface of the moon. ALL still have whats left of the original zincs attached, the zincs oxidize at a rate of about 10 faster then iron....

Lloyd:
   Since the best that I can hope for is to "sort-of" protect the boiler by putting anodes where I can get to the iron surface, I think that I will have to use barrier PEX.

Regardz,

Wayne Stayton

If you added enough anodes to the boiler that would provide any protection, then I think you would have to cover 100% of the inside boiler surface...bc the only thing the anode is going to protect, is the interface between the annode and the boiler surface...maybe out to 2 thnds of an inch.

Lloyd:
About "succintness":

  When somebody asks me a legitimate question like "How does a nuclear submarine work?"  I just can not bring myself to answer with a short "Good!" and let it go - I think if they asked the question, they really want to know, and I should answer as fully and completely as I can.  Since I am 64 years old, it seems unlikely that I can retrain out this response form my repetoir!!!  Sorry, what you see, is what you get!  If it really bothers you, you can solve the problem by only reading as far as my id and then skipping to the next response!

  Thanx all, for the inpuit - you have narrowed things down for me!

Regardz,

Wayne Stayton

Wayne,

Yack all you want, but this forum is a community, "A Crowd Source Community", so when you ask a question, everyone benefits the true answer. When you ask the right questions succinctly, everyone benefits the answer. That's the beauty of community, and crowd sourcing.

Every time you pose a question, and feel the need to regurgitate the same information as was posted in you first post, at least break it down into succinct bullet points, that way the community can provide an answer, to a question that isn't muddled

Lloyd:
  Thanx all, for the inpuit - you have narrowed things down for me!
Regardz,

Wayne Stayton

No the community has narrowed it down for you.

Lloyd

[WGB]

Well if you use an FDA pex for all then you risk all of your investment in corrosion loss to the boiler/engine/iron....It'll be cheaper to install, but in the long run it''ll cost you some IRON.

If you use all barrier pex, including for domestic water, then you'll pay abuo a third again as much for the domestic supply, and it might not be FDA appoved, so you have factor in the loss of life.




Not sure who stated this, years ago I use to get dual rated pex. Was about the price as pex for domestic plumbing, non-barrier.
I can't remember if it was B or C type, anyway it's still in many jobs no problems, used crimp rings.
Company was bought out by Wirsbo and was soon off the market!
Sure wouldn't want a product like that out there! LOL.
I got it from Northern Wholesale in Minnesota.

[WStayton]

Lloyd:
 
  You said:  "Google "pex law suit" you'll find most are related to leaking joints, from said use of compression fittings. Most plumbers I know that have a pot to p*ss, won't use compression fittings bc of the liability."

  Do you think this is a factor in my heating system, where the pressure is going to be only from a head of four feet, or, so , depth of water - maybe 2.0 psi max???

  For the domestic water supply, I guess I have to rethink.  Is there some easy way to tell if a particular hunk of PEX is approved for potable water, or not?  I would THINK that PEX that comes in red and blue, as in hot and cold water, WOULD be okay, but rather than be poisoned, I would prefer to KNOW, not just THINK!  <grin>

About steel boats corroding when out of the water even though having "zincs":

  When you pull the boat out of the water, you no longer have a uniform environment to distribute the electrical charge from the rusting steel, so you have the localized problems that I am worried about in the inside of a boiler.  The zinc is only going to protect an area equal to the area over which it can influence the electrical charge of the surface, whether that comes from a stray electrical current, rusting, or dis-similar metals.  When you clamp the zinc in the middle of a DRY panel, it can only influence the surface that it is actually touching, so, ideally(?), you would have a rusted hulk with zinc shaped "patches" remaining.  <grin>  Of course there is always going to be SOME water around from rain/condensation/etc., so the preserved patches will be slightly larger than the zincs.  Does this mesh with your observations???


  I was basing the use of compression fittings on the website posted which listed compression fittings as useable for most types of PEX.  So are there other parts of this posted source of information that I should take with a grain of salt?

  Again, thanx for the information guys - especially that which differs from the published "knowledge"!

Regardz,

Wayne Stayton

[Lloyd]

Hi Wayne,

FDA approved pex by a reputable manufacture will either state it on the pipe, typically by the manufacture code, they will also have the information published in their, literature, and most likely on their web site. If your buying from an unknown manufacture you need to be careful.

Just look at the Chinese manufacture, and what they put in human milk supply and baby infant formula. They ended up killing 100's and making thousands sick.

Your still missing the point on metal erosion. Metal erosion from oxidization, is not metal erosion from galvanic corrosion(electrolysis) Zinc's and other anodes protect from galvanic, not oxidization corrosion.

Paint and  other methods  of coating protect from oxidization. Also metal can't corrode in an oxygen starved environment, except for active stainless steel, unless it's from galvanic or cavitation corrosion.

Now a boiler/engine water system done right has little oxygen, but you have other corrosive issues, includin to acidic water, to alkaline water, you can get electrolysis on a closed loops system using fresh water, but that risk is only high when the water becomes acidic. One other form of corrosion in a closed loop system is cavitation corrosion( I'll let you google that)

But for the last time anodes will not stop a boiler/engine system from oxidization corrosion.

Lloyd