Pex I.D. ?

[Boardroom]

Hi gang.
I put an addition on my home about 13 years ago and had a plumber install radiant floor in the basement portion. It was fueled by my oil fired hot water tank. I would now like to hook it into my boiler system but am unsure about whether the plumber installed the oxygen barrier pex in the concrete. Here is what it looks like. Is it appropriate?

 

[BoilerMan]

I don't think anyone (accept wirsbo a long time ago) makes a tubing that is rated for potable water and has an oxygen barrier.

I'm going with it is not a barrier tube. When you say it was heated with hot water tank, do you mean oil fired water heater for domestic hot water?

You can use a flat plate heat exchanger and used this tubing in an otherwise closed system. Non barrier tubing is an open system.

TS

 

[Boardroom]

Yes. It was hooked into my domestic hot water so it was an open system. I figured it was not oxygen barrier but wanted a few opinions before I make my next move. Thanks for the input.
What if I only had about 12 inches of this pipe sticking out of the floor before it connected to my oxygen barrier tubing? Is even a little of this pipe still going to cause a problem? I assume the stuff in the concrete would be fine.

 

[Bob Rohr]

Encasing it in concrete will not stop the O2 ingress. A few choices, separate it with a heat exchanger, or add a oxygen scavenger chemical from time to time.

If everything in the system is non ferrous it would be fine. Boiler, pumps, valves, manifold, expansion tank, etc.

 

[Boardroom]

I was afraid you were going to say that.
Separating it with a heat exchanger sounds like the bigger job as the floor would then become it's own closed loop. I assume I would need a pump to pump the floor side as well as a water fill, small expansion tank and prv.
I suppose the heat exchange does not need to be instantaneous (my Alpha only pumps when required). I could have it so that when the floor calls for heat a zone valve opens up and hot water would go to the boiler side of the exchanger. Right now I have a 15-42 pumping my floor. It could either circulate the floor water constantly through the exchanger or I could have it start at the same time the heat call comes.
Then again I would probably have to go out and buy a new stainless pump.
Am I on the right track?
I am not that familiar with the oxygen scavengers.

 

[Bob Rohr]

I was afraid you were going to say that.
Separating it with a heat exchanger sounds like the bigger job as the floor would then become it's own closed loop. I assume I would need a pump to pump the floor side as well as a water fill, small expansion tank and prv.
I suppose the heat exchange does not need to be instantaneous (my Alpha only pumps when required). I could have it so that when the floor calls for heat a zone valve opens up and hot water would go to the boiler side of the exchanger. Right now I have a 15-42 pumping my floor. It could either circulate the floor water constantly through the exchanger or I could have it start at the same time the heat call comes.
Then again I would probably have to go out and buy a new stainless pump.
Am I on the right track?
I am not that familiar with the oxygen scavengers.

Correct, with a HX you have two separate systems, both needing pumps, expansion tanks, air purgers, etc. The HX pump would run only when there was a call for heat.

Oxygen scavengers are a chemical, typically a liquid the would be added to the system from time to time. Look up some of the wood boiler suppliers that advertise here, they have access to the products. Same for OWF dealers.

here is a good explanation on how they work.

http://www.woodboilersolutions.com/otherproducts.cfm

 

[Boardroom]

Thanks again Bob.
Using the oxygen scavengers is definitely the easier way to go but it simply bugs me that I spent time and money keeping the rest of my system oxygen free and now am considering throwing in the towel on that and letting oxygen into my system. I am not sure that I can make the heat exchanger method work though. I have added a simple sketch of my distribution manifold. I heat my house with cast iron radiators which don't require a lot of flow. My Alpha only pumps when there is a call for heat and I rarely see it say it is pumping over 2 gallons per minute. Would this be enough flow through the boiler side of the heat exchanger to create the required amount of heat on the floor side? My concrete floor is 400 s.f.