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Polybutylene pipes used for hydronic heating system

eugekhaneugekhan Member Posts: 3
Hello - I'm looking to buy a house with polybutylene pipes. My inspector mentioned in his report that the hydronic heating system uses polybutylene plastic plumbing supply lines. Please see excerpt from his inspection below.

"Polybutylene plastic plumbing supply lines (PB 2110) are installed in the subject house and used in the hydronic heating system. (Picture 1 thru 4) Polybutylene has been used in this area for many years, but has had a higher than normal failure rate, and is no longer being widely used. Copper and Brass fittings used in later years have apparently reduced the failure rate. Unable to verify fitting material used as the pipes are under the floor."

I wanted to find out #1, how severe of an issue this is and #2, what kind of remedies/solutions we could undertake to mitigate this issue.

Thank you!


  • ZmanZman Member Posts: 5,831
    Do you know which Poly you have? Is it red or grey? Are there any markings? Do you have pictures of the the tubing or fittings.

    It is pretty unlikely that there are fittings buried under the slab.
    The grey poly did not have an oxygen barrier which brings about separate issues.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • eugekhaneugekhan Member Posts: 3
    Thanks @Zman

    It is Light grey color and has PB 2110 marking on it. The house was built in 1990.

    Is this a deal breaker? The house is around 5000 SF so it seems catestrophic if we would need to replace all the piping
  • JUGHNEJUGHNE Member Posts: 6,924
    I have about 2000' +/- of red O2 PB buried in concrete floors since 1995, in my house.

    The only issue was the connections at the Infloor pump manifold. Spliced on to the tails with PEX and new manifold.
    The mixing valves work on 2 out of 3 units.
    Still have original pumps running.
  • hot_rodhot_rod Member Posts: 13,318
    Looks like it has been worked on already, some Pex splices.

    The tube really was not the main problem with the failures, it was the crimp rings, acetyl fittings and some brass that dezincified.

    However if it is a non barrier tube, oxygen gets into the system and will speed the corrosion of any ferrous metal in the piping.

    What type of boiler? A water sample from the boiler would maybe tell how much corrosion is going on.

    If the system heats well, and no leaks in the tube or manifold the system could be upgraded with a heat exchange between a ferrous, cast iron boiler and the tube. Stainless circulators and special expansion tank.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    The magic is in hydronics, and hydronics is in me
  • ZmanZman Member Posts: 5,831
    It's a tough call. As Hot rod mentioned, you will need to isolate all ferrous metals if it has not been done already.

    I would be comfortable that the tubing running at low radiant temps will last for many more years. There really were no major failures of the tubing itself in closed loop heat systems.

    What always scares me is the perception that future buyers may have. You may live in the house for 10 years and have no issues at all. When you go to sell it you will run into inspectors and buyers who are in the same shoes you are in today.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    STEVEusaPAeugekhanLarry Weingarten
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