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Condensing boiler piping mix supply and return

Awill10 Member Posts: 2
I am a novice homeowner who just had a new combi system installed (ibc sfc-199) and have a question with how the piping was installed. I included images of the piping. Basically when I look at the piping it seems that the boiler supply and return meet and mix in the primary loop before heading to the radiators, so the water being supplied by the boiler is actually cooled by the returning water from the radiators before heading back upstairs. My Intuition would think that the T connectors should be the opposite - as in the supply T would be closest to the circulators and the return T closest to the return pipes coming from the radiators. In the current setting it seems like the colder return water from the radiators mixes with the hot water from the boiler, then that mix water heads both up to the radiators from the circulators and also into the return of the boiler. Hope the diagram helps explain.


  • Zman
    Zman Member Posts: 7,472
    edited November 2021
    You are correct and the manufacture agrees with you. Should be a simple fix.
    Otherwise, the workmanship looks great. I bet it was an honest mistake.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • psb75
    psb75 Member Posts: 730
    That was a good "catch" for a novice homeowner. Reading the I & O manual is a good thing. I agree with Zman that it was an honest mistake. Kudos to your installer generally for following Primary-Secondary principles of hydronic plumbing! That is why this will be easy to correct.
  • Awill10
    Awill10 Member Posts: 2
    Appreciate the reply Zman. Will be following up with installers in that case. Thanks!