PEX failure or something else?
This story was shown to me tonight. It’s about a failure of a pex RFH install. I’ve spotted a coupla things that aren’t like any install I’ve ever seen. What’s your take on the article and the description of the system? Here’s an excerpt:
http://www.kirotv.com/consumer/1954263/detail.html
Heating System Can Cause Heavy Damage
Some Hydronic Heat Systems Could Be Disasters Waiting To Happen
POSTED: 5:45 p.m. PST February 3, 2003
Bebe Emerman
KIRO 7 Eyewitness News Consumer Investigator
It’s a disaster waiting to happen — and it could be inside your home!
A KIRO 7 Consumer Investigation exposes a defect in your heating system that could cause heavy damage to your home.
KIRO 7 Eyewitness News Consumer Investigator Bebe Emerman has the warning that could affect thousands of homeowners. The problem centers around a plastic pipe is made of a material called PEX. It’s used in a popular and inexpensive heating system called hydronic heat. It’s in homes and condominiums all over Western Washington.
But, as our KIRO 7 Consumer investigation reveals, this system that’s supposed to keep you warm and cozy could leave you cold and wet.
“[I] turned on the light and all I saw was water,” says Melanie Hoshino.
It was Christmas morning when Hoshino found hot water gushing from these plastic pipes in the garage of her three-year-old condo.
Replies
How unfortunate.
Plasco's tubing is cross-linked via the silane method, which is about the worst you can do. With the other two methods (andy) Engel and irradiation, the cross-linking occurs between carbon molecules. The silane method links silicon and oxygen molecules. The silane link is weaker and not as stable.
If these people had "plastic pipes" in their garages, it sounds lke the pipes were visible and could have suffered exposure to UV light. The UV will further damage the pipe, causing brittleness.
I derived from the article that more pipes broke while the plumber was making repairs. That probably backs up the guess that the pipes had become brittle.
Even in a garage, I don't think they'd have frozen. If the system was not circulating and the water did freeze, brittle PEX wouldn't be able to handle the expansion.
180 degree water? Was this supplying baseboards? At what psi? Add in a llittle black slime...oy!
Some things aren't worth skimping on.
Thanks! The 180 and the mixing of plumbing and RFH caught me right away. Our pex is specifically not for potable water--marked right on the tube. Didn't know about the three methods--thanks for the education. Only have used Wirsbo--thank god!
It appears that the failures were all above floor at the manifolds. UV exposure sure bears checking into.
I can see it now.... CSI:Breaktime! C for Construction. Part of the Taunton Family Network.
Cloud,
Did a quick search, here's a little more info onn PEX-A, -B, and -C:
There are three primary methods for producing PEX tubing.
1. The "Engel" or peroxide method employs a special extruder with a plunger action where peroxide is added to the base resin and through a combination of pressure and high temperature the cross-linking takes place as the tubing is produced.2. The "Silane" method of PEX production involves grafting a reactive silane molecule to the backbone of the polyethylene. The tubing is produced by blending this grafted compound with a catalyst which can be done using either the Sioplas method or by using a special extruder it can be done using the Monosil method. After extrusion the tubing is exposed to either steam or hot water to induce the final cross-linking reaction in the tubing. 3. Electron Beam crosslinking takes place when very high energy radiation is used to initiate molecular cross-linking in high density polyethylene. This product is extruded like normal HDPE then taken to an E-beam facility and routed under a beam or ray in the accelerator where it is dosed with a specific amount of radiation to release the hydrogen atoms and cause polymer cahins to bond or link to the open carbon sites.
In European standards these three methods are referred to as PEX-A, PEX-B and PEX-C,...
Wirsbo and Rehau are PEX-A, they are the two "-A" tubes that are available from the two supply houses near me.
Hi,
I'm completing an addition where the heating company used a product I've never seen before for radiant floor heat. It's called Kitec and is a flexible aluminum tube with plastic lamiated to the interior and exterior.
Seems pretty unlikely to leak for a long time.
It is designated by the company that makes it as, Kitec PEX-AL-PEX.
I know it doesn't address past installations but if I ever do an installation in my own house I'll consider this stuff.
Tom
Aren't these systems filled with some type of anti freeze solution to keep them from freezing up.
The installations I've seen have not had any additives. It is not necessary unless there's a chance of freezing, and that's improbable with what we're building. So no, it's not something that has to be done.
Does anyone know if Radiantec tubing is Pex A, B, or C?
They call their tube PXC...dunno if that gives a clue. Nothing definitive on their website.
Like Cloud, I couldn;;t find out.
I called them quite some time ago and asked. The reply? "What does A, B, or C mean?" I asked how it was cross-linked, and they had no clue. I asked who manufactured the tuubing, again, no idea. I asked for a tech sheet and it ever arrived.
Someone up there must know the answers, but the peope I spoke to that day had no answers.
Some closed heating systems do contain an anti-freeze. Not all do, nor is it always necessary, even in freezing climates.
In this instance, it's tough for me to tell just what the PEX was used for. RFH, baseboard supply, DHW, or all of the above.
The hvac contractor I use for most of the houses I design uses both Wirsbo and Kitec. In researching this thread, I saw a mention that if the alum sheathed pex ever freezes, the alum will expand and not return to shape, making it difficult or impossible to fit into the fittings. Haven't had the chance to ask my friend.
Cloud,
The worrying thought I've had about Kitec aluminum pex tubing is related to the old problem with aluminum wiring from the 70's.
Aluminum is brittle. Heating and cooling cycles mean expansion and contraction. Does this mean metal fatigue and breakage?
I'm sure alloys have come a ways since then but who knows?
Tom
Tom,
I meant to add a bit regarding your earlier post about Kitec. It's good stuff. Feel comfortable and confident using it.
I believe the problem with aluminum wiring has to do with the wire sort of squeezing away from the terminals leading to aluminum oxide formation. Aluminum oxide is more resistant to electricity than aluminum, so heat would be produced, which would accelerate the production of aluminum oxide, etc.. These are actually problems that could be dealt with, but weren't, but its all about electricity and aluminum, not the aluminum.
If an aluminum airplane can last 50+ years, I'm sure a heating pipe would to. However, things to consider would be I don't think you could embedd the aluminum in concrete, because the two aren't compatible. Plus if water came in contact with the aluminum, especially if it wasn't really pure, you'd get a reaction as well. Either way, youd would have to hope the plastic coatings are never compromised anywhere.
Besides pex gives a little with concrete expansion and contraction, aluminum won't, at least for long, so I'd be surprised if its recommended for embedded installs.
>so I'd be surprised if its recommended for embedded installs.
S-U-R-P-R-I-I-I-I-I-I-S-E !
http://www.ipexinc.com/kitec/warmritefloors/warmrite_floors.htm
Ok, so I am surprised, but I'll wait 50 years and see how well aluminum deals will cracking, expansion, and all the other joys of concrete.
"Ok, so I am surprised, but I'll wait 50 years and see how well aluminum deals will cracking, expansion, and all the other joys of concrete"
Exactly the reason I use Wirsbo, I started using Wirsbo in radiant floors about 10 years ago and at that time when I was researching different products Wirsbo had been under long term labratory tests for about 25 years in Sweden. That would make it 35 years old now. I have worked on a reno that had kitec installed approx. 5 years ago seemed fine at that age but I still feel more comfortable with Wirsbo. I installed 132,000 ft of hepex last year and sales are increasing every year. I am glad I have never put in any Plasco pex as a lot of my competitors are doing here in B.C. where it is manufactured.
Black water coming out of the domestic water supply. supposedly coming from the heating system.
Dose a state pluming code allow for the possibly of mixing heating system water back into the domestic water supply.
I would have thought state pumbing code would have required a fill tank and float valve. It would act as air break with a check valve to keep back flow into the domestic water supply.
Lots of things don't add up - starting with "... used in a popular and inexpensive heating system ...", moving on to "... because hydronic systems are tied into plumbing systems ...". But that could just be the notorious accuracy of the media.
I never heard of Plasco before, but I bet they'd be outa business quick if their PEX only lasted 5 years. Plus the stuff is usually UL and all certified (asuming of course the installer used the right material for the job and not potable water PEX). The hydronic/plumbing tie in, black slime, etc., makes it sound like the design and install was done by idiots, unless codes are really lax in that state, and just meeting code is good enough.
Maybe the lawyers figured they couldn't get enought money out of the installers.
Of course, it could also be a bad batch. It'll be interesting to see how this pans out.