Do I need Oxygen Barrier PEX for my outdoor wood boiler or hydronic system?
Only if it is a CLOSED system which would also likely be pressurized. Typically, a closed system would not require require filling of the vessel, nor a rust inhibitor water treatment. Only about 5% of outdoor wood boilers are closed / pressurized systems.
OPEN systems do not require O2 Barrier for their insulated PEX pipe.
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