DO I need oxygen barrier pex

[jmemmert]

I am about to install a woodmaster 4400 outdoor boiler. I plan on heating my house and domestic water with it. My dealer said there was no need for oxygen barrier pex since I am not doing radiant floor heat, but I thought check with everyone on here before buying my pex.
Thanks!

 

[machinistbcb]

Your woodmaster boiler is likely not pressurized so there is no real advantage to use oxy barrier pex since it will already be an open system and allow oxygen into the water. The only thing you can do to help prevent corrision is add treatment chemicals.

 

[windthrown]

No need for oxygen barrier PEX. We used standard PEX on our Central Boiler system and it works fine, and has run for 3 heating seasons now.

 

[KsWoodsMan]

OK ,I just gotta ask this.

What is the purpose of Oxygen barrier pex-line in an OWB installation ? To start with, water is comprised partially of Oxygen. Is there that much porosity in some pex-lines that it will allow oxygen to migrate into a pressurised stream of water?

If corrosion was that much of an issue, why not electoplate the inside of the vessel with something more durable?

Maybe I'm just looking at it from the wrong view. I don't see the point to oxygen barrier pex but hope someone can offer an explanation.

 

[jmemmert]

ok, thanks everyone. That clears it up for me.

 

[Marklambert61]

Pump

If you plan to use non O2 pex you will need a bronze pump...

Mark

 

[KsWoodsMan]

If you plan to use non O2 pex you will need a bronze pump...

Mark

Is this because Oxygen is less reactive with bronze than say , nylon (plastic) or cast iron over the service life of the pump ?

Does the extra expence for O2 barrier lines justify the cost of not using a bronze or brass pump ?

I'm not trying to be argumentative or induce someone to buy less than they need. I'm just curious what reasons there are for additional costs when they may not be warranted for the situation.

 

[abohac]

I am about to install a woodmaster 4400 outdoor boiler. I plan on heating my house and domestic water with it. My dealer said there was no need for oxygen barrier pex since I am not doing radiant floor heat, but I thought check with everyone on here before buying my pex.
Thanks!

Nope. I didn't use it in my house (basement, garage and tled floor areas) but after doing my dads shop floor with Kitec I sure wish I had used it in my house. It is a lot easier to work with.

 

[Tracker83]

There is NO reason to use oxygen barrier PEX in an OWB. OWB's are not pressurized systems, therefore they are vented to atmosphere. Mine has a 2" diameter vent right out of the top of the stove (common with most). WAY more O2 will enter the system via that vent then will ever enter the system by permeating the PEX piping.

That being said, it may be benificial due to the expansion/contraction properties, but it is certainly NOT needed for the oxygen blocking properties.

 

[windthrown]

Using corrosion inhibitors in the OWB loop will also prevent any corrosion in the pump, by converting the pH to a level that prevents the steel and/or any other metals from oxidizing. As someone said above, in an open loop boiler system (non-pressurized) there is always O2 getting into the boiler water from the vent.

There are two types of Ox barrier PEX: one has a polymer laminated to the outside surface (or sandwiched between the PEX layers) that prevents oxygen from penetrating. The other type has a layer of aluminum embedded between layers of PEX to provide an oxygen barrier. Ox barrier PEX is designed mainly for using in applications that are sensitive to oxygen, like closed loop pressurized hydronic floor heating systems with metal pumps.

In an OWB non-pressure loop, you don't need it. Plain PEX will work fine. Ox barrier PEX is said not to flex and/or expand and contract as much as regular PEX does though. So in some cases it might be better if expansion is an issue.

 

[Jkebxjunke]

so it sounds like i wasted my money on barrier pipe and stainless steel pump although I got a really good deal on it

 

[windthrown]

so it sounds like i wasted my money on barrier pipe and stainless steel pump although I got a really good deal on it

Yah, if you plumbed them on a steel OWB, you really did not need them. I used plain PEX and a 007 Taco pump. I used brass fittings out the tank, and copper connectors (they were a lot cheaper then).

 

[mtfallsmikey]

Not really a waste...bronze/stainless pumps will last forever on an OWB. Just make sure you use your mfr.'s recommended water treatment chemical and plan. Since I do some extensive water treatment on the cooling towers and condenser water systems where I work, I've got a fair amout of experience in that field...thought the CB water treatment was a joke, but it's the real deal...my water treatment guy could not come up with any better combo of chemicals than the CB stuff. :deadhorse:

 

[MS-310]

If you plan to use non O2 pex you will need a bronze pump...

Mark

OK I dont think so, I have never heard that and been doing this for almost 10 years. I am not saying your wroung but i want to know!

 

[windthrown]

The vast majority of non-pressurized OWB pump failures are supposed to be due to cavitation (pitting). I put the pump at the lowest point in the CB heating loop to give it a little 'extra' pressure and help avoid that. I do not know if brass or SS pumps will help avoid cavitation or not. Not that Taco pumps are that expensive to replace (compared to the old electric heating bills). The pump I installed on a CB OWB loop is still working fine after 3 heating seasons. The hydronic floor pump is a Taco 009, but it is in a pressurized floor loop and thus should last a lot longer. We shall see...