Wirsbo pePEX

[kurt]

Saw a place with a crappily installed radiant system from '91-ish today. Wirsbo pePEX tubing.

No apparent oxygen barrier; I could shine my flashlight on it and see through it (sort of a translucent glow).

Been googling and looking for problems, can't find any, but old crappily installed radiant with old tubing lacking oxygen barrier makes me really nervous.

Anyone know anything about this stuff?

[Chad Fabry]

No oxygen barrier isn't a bad thing for the tubing, it's a bad thing for the equipment. I'm not sure about the 90's but today an oxygen barrier does not preclude translucence.

Been googling and looking for problems, can't find any, but old crappily installed radiant with old tubing lacking oxygen barrier makes me really nervous.

Put that in your report.

[kurt]

Good idea.

My IR showed the tubing layout to be a complete pile of shit; I suspect they placed the concrete and simply mashed the tubing down into the mud.....no grid whatsoever, it's all over the place.

So, I have plenty to can the install including a couple of possible leaks. I was just looking to see if there was a problem with this particular tubing. A lot of tubing from this era (think Entran) was crap, so I'm nervous.

[Tom Raymond]

My system is hePEX from '05. I can see through the oxygen barrier. No trouble with the tubing but the Wirsbo manifolds suck. The bodies are very nice heavy brass castings but the sweat adapters and caps are thin machined pieces. Both manifolds leak at both ends and the mixing valve leaks at the sweat adapters and the packing nut at the start and end of the heating season when there are long stretches between firing cycles. There is enough variance in the expansion rates that the O rings loosen up and drip. Very glad they are in my basement and not in a wall.

On a side note, how were you able to see the tubing layout in concrete? I have only been able to do this if the system has been off and I fire it. If the slab is warm I might be able to vaguely locate a tube every six or eight feet.

[Denray]

Since I was ignant I looked it up:

One of the most common questions you face when starting on a plumbing or radiant heating project is whether to choose PEX tubing with oxygen barrier or non-barrier.

The main difference between the two types is the external polymer coating of the oxygen barrier PEX tubing, which makes the tubing prone to oxygen diffusion. Oxygen barrier PEX is used in radiant or hydronic heating applications only, where cast iron or other ferrous components are present in the system. Since contact of oxygen molecules in the water with ferrous parts in the system results in rust, oxygen barrier helps to prevent ferrous components from corrosion.

Oxygen barrier is also called EVOH (Ethylene Vinyl Alcohol), which is simply the abbreviation for the polymer.

DIN 4726 is the standard that can commonly be found imprinted of the oxygen barrier PEX tubing and shows that the oxygen diffusion barrier requirements are met.

Non-barrier PEX tubing, or simply PEX plumbing tubing is used for plumbing applications. Since there's always a supply of fresh water from a water heater or a water main, oxygen molecules will always be present in the system, so there's no need for the oxygen barrier.

If you already have the tubing but don't know which one you have, bring it to the light and take a closer look. If the tubing has a shiny surface - it's PEX with oxygen barrier; if the surface is matte - it's non-barrier PEX. Most manufacturers also have the type of PEX imprinted on the pipe. Don't get confused with colors, as they do not idicate the type of tubing, they are used for color coding purposes only.

[Marc]

Do you mean that the barrier is to keep oxygen from diffusing out of the pipe?

Marc

[Denray]

It's from Google. Keep it out so as to not rust parts in the system.

[Denray]

Last week I looked at a house with electric floor heat for the master bath. After an hour the marble floor was still not warm. Down in the crawl below it was very warm.

[kurt]

Thanks, that's useful.