Anyone seen this....

kcopp

happen before.... 12 yr old system, City water supply, Weil GV boiler supposed barrier EPDM tubing. Extrol tank, 2 Sparco mixing valves and 4 of these 007 looking and performing not so great.... no wonder

Ironman

Looks Like...

Something's growing in there. I don't think that would be possible unless there was o2 present.



Maybe someone else can I.D. it.

Paul Pollets

02 diffusion

Good example of oxygen diffusion from non-barrier tubing. Seen it many times. EPDM tubing does not have an 02 barrier. Separate the tubing water from the boiler using a Taco-X-Block and treat the water on the tubing side with cleaner and an 02 scavenger. Rhomar makes good boiler cleaning and system chemicals. Stainless or bronze pumps should be used when non-barrier tubing is installed.

kcopp

Odd thing about....

this tubing is that is is supossed/ marketed as having the O2 barrier. Its Heatway onyx. The customer does not want to opt for the HX as would be best. So I have flushed it out w/ a bunch of water, let Rhomar 9100 run in it for a month then added the 922. I will be back next fall to repeat....

Mark Eatherton

My friend The Heatmeister...

see's this ALL the time. And yes, the tubing DOES have a Mylar O2 barrier, but, and this is a BIG but, it was intended to stop O2 flow through the side walls of the tubing.



At each point where the tubing is cut to connect to a manifold, there is a path that is PARALLEL to the O2 barrier (inner tube lining) that allows oxygen to flow into the tubing and into the fluid it is carrying.



That is just MY theory. But the evidence in the field, as is being found by more than one person, indicates that this is definitely an ugly issue. The more branches on a manifold, the ore corrosion that will be seen.



Kevin, did you happen to check the pH of the fluid?



ME

kcopp

I did not....

It did not occur to me.. it will now. I The other thing is that when the tubing starts to degrade the rubber makes a huge mess. I think even worse than non barrier pex. The EPDM also has to run at a higher temp w/ staple up  than pex w/ plates. Higher temps... more O2. correct?

Mark Eatherton

Correct...

and the more oxygen, the more oxidation, including the rubber.



Check the pH on the next one you find. It's usually pretty low.



ME

NRT_Rob

pretty small

vector for oxygen diffusion. percentage of coverage is supposed to be a big player there.



I would be more inclined to suspect a slow leak somewhere and makeup water.

kcopp

everything was ....

OK until about about  2 years ago....  they the odd things started happening. Mixing valve seizing, extrol tanks failing and spirovents plugging. The system is staple up.... I have been in the crawl area and it looks clean and dry. Lets hope the system will stabilize w/ Rohmar and the new stuff.

KCA_2

There is more than one

place for O2 to get into the system...  That's why I'm not a big fan of O2 barrier tubing...  With O2 barrier tubing one feels like that shouldn't happen and leaves a system alone for years or for ever..  Until  something fails and they replace it...

I'm more a fan of yearly maintenance and chemical additives...  A little bit of Sodium

Molybdate goes a long way...



:-)  KCA

kcopp

Fair enough....

so you would put in regular pex tubing (aquapex) w/ ferrous circulators and the like and just come back on a yearly basis and treat it w/ O2 inhibitors? Hmm... one particular guy around these parts did that 20 years ago w/ PolyButylene.... didn't really turnout all that great for him.

Mark Eatherton

Not a make up issue...

Trust me when I say that there is no one as thorough as Der Heatmesiter. I am more than certain that he has eliminated a leak as a possible cause, and its not just one or two systems that he is seeing this in. It is ALL of them. The more manifold branches, the worse the corrosion. I wish there was a simple answer/solution to this problem...



There is also a propensity for oxygen to infiltrate a point faster when there is a MBR in place. They have a tendency to make the water oxygen deprived, and as a result, the places where O2 can ingress does so at an elevated rate. This was seen during the testing of Entran 2.



ME

KCA_2

MBR?

What's an MBR?     A Master Bathroom?



Ya know....  I spent a long time looking into corrosion... Some of that time I was with a Chemical Engineer.....  I even looked into small electrical currents and grounded systems for prevention at one time..  It's O2 and treating the systems is the only way to fix it...  The spray on O2 barriers are still, I believe, water soluble....  What football stadium was it that had the boiler go bad because of it...  It was 15 years ago or so...  All the pex had a O2 barrier and they buried the Pex under the sod....  Watered the Sod and the Pex lost it's O2 Barrier...  That's not necessarily a problem but no one was maintaining the systems or Boiler because they were O2 sound....  Right...  OOOPS....  The boilers were millions apiece and they ended up replacing them...  You have to maintain the systems so if you're doing that.....  Why use O2 barrier at all...  It costs way to much .....  Just my thoughts... 



Also...  I stopped using Spirovent type air eliminators years ago too....  They just work to darn well.... 



:-)  KCA

kcopp

What product....

do you use? Rohmar or fernox or something else. ty,kpc

Mark Eatherton

MBR = micro bubble resorber...

i.e. Spirovent :-) as well as others.



Back to scoops eh?



I've seen the EVOH barrier on older PEX shed like a snake skin on a snowmelt system. Fortunately, they were keeping an eye on the pH and induced corrosion inhibitors on a regular basis.



Have you ever seen PEX with the exterior EVOH scratched by a joist hanger or nail? If forms an ugly dark scar (ferrous oxides) where the barrier was voided....



ME

KCA_2

Yea... I figured that out Mark...

MBR.....  I just don't call them that...  It's always just been an Air Eliminator...  Lol



I don't use any formulated additive....  To expensive and ...well .....  Just to say that I use more Sodium Molybdate than anything else...  Need to keep about 2-4 PPM in the system much more causes it's own issues... 



Take a cup of water and a nail....  add stuff and see what works...  Test for it...  See how the chemicals work together....  It is fun....  Read, Study, experiment, or use a pre-made additive....



It works for me....



But O2 barrier.....  I'm sorry ...  I'm just not a fan....  Doesn't mean that you can't be....



:-)  KCA

NRT_Rob

skipping a few things

1. not all o2 barriers are on the outside.

2. not all o2 barriers are even EVOH (see, PAP tubing)

3. there are millions and millions of feet of barrier pex installed without significant corrosion issues in the systems.



for huge commercial systems you might have a better point, but residentially the chemical additives are probably more problematic than helpful.

kcopp

The real prob...

w/ chemicals in residential are that homeowners don't keep up w/ them. They forget or don't want to be bothered....