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Replacing 30 year old boiler with Navien combo 240/110H

suflynn
suflynn Member Posts: 1
in Gas Heating

When Replacing a 30 year old boiler with Navien combi 240/110H, is it necessary to replace the gas line? I am getting conflicting information. Thanks

Comments

  • PC7060
    PC7060 Member Posts: 1,625

    depends on the size of the current gas line, gas pressure (4”WC or 2psig) and the max BTU of combi boiler.

    Mad Dog_2GGross
  • pecmsg
    pecmsg Member Posts: 6,009

    and the size of the combo

    Mad Dog_2GGross
  • EBEBRATT-Ed
    EBEBRATT-Ed Member Posts: 17,705

    The gas line shouldn't have to be replaced with a new boiler unless the new boiler is larger than the old one.

    But if the original gas line was undersized or not correct for some reason then it would need to be brought up to code.

    Mad Dog_2
  • HVACNUT
    HVACNUT Member Posts: 6,744

    Reading is fundamental.

    Screenshot_20250424_180004_Samsung Notes.jpg
    Mad Dog_2PC7060
  • PeteA
    PeteA Member Posts: 285

    do you have a picture of your old boiler and its nearby piping as well as your gas meter and piping? This will give folks a better idea how to answer your question but your installer is going to have the final call because he will know/see things in your overall gas usage that we won't see in your photos.

    Mad Dog_2
  • GGross
    GGross Member Posts: 1,492

    Looks like that boiler has a 199,000 input for the DHW so you need to make sure your gas line can support 199,000 BTU/hr at a 0.5"wc pressure drop or less.

    Ironman
  • SuperTech
    SuperTech Member Posts: 2,581

    Why does it have to be a Navien? That would be something I would recommend avoiding. Actually I would recommend avoiding installing a combi altogether.

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