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Non-barrier pex suppling Buderus panel radiators

solradman Member Posts: 57
I looked at a job today where the home owner was completing an addition needing 4 new Buderus panel radiators to heat a bonus room above a garage. The plumber that installed the system (retired and moved away) ran 3/4" pex from the mechanical room to a 4 port manifold and 1/2" pex to the radiator locations using non-barrier pex, When I pointed this out he stated the existing top floor rooms all have panel radiators and were plumbed the same way. The system has been running for over 6 years with no problems. Boiler and plumps are stainless steel, all near boiler piping and components are copper or brass. Main floor is in-slab radiant. Anybody seen or had experience with non-barrier pex in a system like this with Buderus panel radiators?


  • I have one non-barrier job where the Runtal radiator developed a hole and had to be replaced.
    Often wrong, never in doubt.
  • Zman
    Zman Member Posts: 7,375
    If the radiators are thin, stamped steel like Buderus , they will fail prematurely. Inhibitors added to the water will slow the process but not stop it.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
    Larry WeingartenPaul Polletsmattmia2Solid_Fuel_Man
  • hot_rod
    hot_rod Member Posts: 16,878
    edited September 20
    A chemical regiment could deal with that also. Probably a yearly boost would be needed. Rhomar hydronic conditioner work well on non barrier systems. They put a thin protective layer on all the insides of the system pipe, boiler, radiator, etc. Also an oxygen scavenger is in the package. That is what gets consumed and requires boost occasionally. 

    or separate those loops with a HX, additional circ and expansion device
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Paul Pollets
    Paul Pollets Member Posts: 3,524
    I've seen pinholes develop in steel panel rad using non-barrier pex in under 3 years.
  • hot_rod
    hot_rod Member Posts: 16,878
    This LLH was installed on a high temperature, early version rubber hose, system, about 18 months later it had a pin hole. Pretty corroded inside also.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • rick in Alaska
    rick in Alaska Member Posts: 1,388
    I guess the short answer is that it depends. I have systems that have old polybutylene tubing installed with radiant tubing with no issues. But, radiant is at a lower temperature which makes a big difference with oxygen corrosion.
    I would think with all of your parts being non ferrous, you shouldn't have much of an issue, but I would put in boiler treatment just to be on the safe side.
  • mattmia2
    mattmia2 Member Posts: 5,999
    edited September 21
    hot_rod said:

    or separate those loops with a HX, additional circ and expansion device

    But the tubing now buried in the structure to the emitters is non-oxygen barrier. The part that needs to be isolated with the hx is directly at the end of the tubing.

    I'm never a fan of copper baseboard, but that might be your best option here.