Non Oxygen Barrier Pex In-floor

[Armaton]

Mistakenly used non oxygen barrier pex for "Basement" infloor! If I run oxygen barrier for all the rest of my system, do you think the 3 or 4 air separators on the system could keep up with the infiltration from those 12, (2 zones 3 runs each), 18" long 1/2 inch pex lines? Or will the lines in the cement also allow oxygen in? Not certain that I'm gonna like the answer. 1000 gallons in system, separators on boiler, WAHX, and in-floor loops, and I guess I can put one on the domestic hot water loop also. Probably have to use corrosion inhibitor, but do you think I can keep it pressurized?

Brandon

 

[ewdudley]

Air separators only remove whatever gas comes out of solution. The oxygen that does not come out of solution is depleted by participation in corrosive processes. If the system keeps putting oxygen into solution then the dissolved oxygen will be continuously available to support corrosion.

Maybe just put a plate HX on the load side of the mixing valve with a small non-ferrous pump like a Bell & Gossett ECOCIRC that would circulate though the HX and the basement floor. The smaller B&G ECOCIRCs only draw a couple watts and will move a GPM or so.

So there would be a mixing valve and a pump that would serve the basement floor and and other low-temperature loads (if any), and the basement load would have a separate pump for its side of the HX.

 

[Boil&Toil]

You need a stainless exchanger and a stainless (or bronze) pump on that section. Don't rust out your boiler to save a few bucks (it won't save any bucks.) Or, you can use an indirect hot water heater (essentially another form of heat exchanger) and run the loop with a stainless pump off your hot water heater. Check T(broken link removed to http://www.radiantcompany.com/system/open.shtml) for details, they promote this method (especially before they had oxygen barrier tubing - which is when I bought what's in my floor). That assumes that your non-o2 barrier tubing is NSF-PW rated for potable water.

 

[heaterman]

Go with a small plate HX to isolate those loops from the rest of the system. I know it's a few hundred in added expense but it's way cheaper than having a mess to deal with 5 years from now after your whole system is filled with sludge.

 

[BoilerMan]

If that's the only low temp (slab) in the mix, check out the Taco XPB, it incorporates the SS plate heat exchanger, outdoor reset, and the injection control. They are pricy, but can be scored on ebay for about 600 bones. I have one and it works well, and is designed to do just what you are doing.

Do not connect any non-barrior tubing to any heating system....................

TS

 

[goosegunner]

Could he just treat the water?

gg

 

[BoilerMan]

Could he just treat the water?

gg

Water treatment would combat the problem, however separating and sealing the system is the best solution IMHO.

TS