Use of non-oxygen barrier pex pipes

Joseph_4

Hi, I have a customer who had radiant heat already installed in his floor. In one room the contractor used non-oxygen barrier pex pipes. I just installed a brand new cast iron boiler in his house but I am reluctant to hook it up to this room as the oxygen will ruin the boiler. I would like to put in a water heater with its own pump but I was told that it will let in oxygen and make the pump air bound. Does anyone have an actual case that this has happened and if so, how long it takes for it to be come air bound? How often would I need to replace the pump? If i put a spiral vent, can that work to let out the air?

GroundUp

Pipe in a plate exchanger for that room with a bronze or stainless circ and let it do its thing. No need for another appliance. Would obviously need another relief valve, air eliminator, expansion tank, etc as you would with any standalone system but definitely don't need another burner. Plates are cheap

Joseph_4

I was told that the even if i use a stainless steel pump, the pump will cavitate cuz air will be let in and the pump will die.. I figured a spirovent would solve this. trying to see from experience out there.. this would happen i've been told even if i use a separate exchanger.
Thanks
Joe

Ironman

What you've been told is wrong. Do it the way @GroundUp told you and it will be fine.

There are thousands of open domestic systems that have re-circulation pumps and those systems contain more oxygen than your closed loop with non-barrier pex.

Ask your fountain of mis-iformation if he understands NPSH.

hot_rod

Air doesn't get in thru non barrier tube, oxygen at a molecular level is what migrates in thru the wall of the tube. Nothing you can see or measure. A good air purger is needed regardless of barrier or non barrier tube.

Joseph_4

i greatly appreciate the replies from ironman and hot rod.. I wanted field expertise which is what youve given as opposed to the advice i was given by a large design firm as sad as this sounds as per iron man's comments
Thanks
Joe

hot_rod

Personally if it is just one small zone of non barrier I would just add a hydronic conditioner like this Rhomar 922. It was blended specifically with those non barrier tube systems in mind. It will be good for the rest of the system and components also.

Check fluid every couple years, or send Rhomar a sample to test.

Disconnect the system from any auto-fill. Add a low water cutoff or Axiom fill tank.

https://www.rhomarwater.com/pdf/ProTek922_Product.pdf

username1

good info, thank you!