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Concrete Slab, pavers or bricks under Mod/Con Boiler

Javelin Member Posts: 138
Heating Pros, We're most likely installing a Knight Mod/Con boiler with an indirect water heater and floor based expansion tank. Our basement gets damp, but has no standing water where the install will be going, and has a center drain that all things lead to.

Should I put the boiler right on the basement floor, or does it still make sense to raise it up off the floor. Should I pour one big slab (for all 3 appliances) or should I use bricks/pavers individually under each and shim as needed?

Any thoughts?


  • Zman
    Zman Member Posts: 7,569
    Wall mount

    For the indirect and the expansion tank, why not just use pavers? Even if the basement flooded with a foot of water, there would be little chance of permanent damage.

    As for the boiler, mount it on the wall. Many of the systems destroyed by flooding would have done fine if the boiler was mounted 3 feet off the floor. It also cleans up the boiler room and makes servicing a pleasure.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • RobG
    RobG Member Posts: 1,850
    Pavers or slab

    I prefer pavers or solid blocks that way if one appliance ever leaks (and it will) only the base of that individual unit gets wet. With a solid slab they will all get wet


  • Javelin
    Javelin Member Posts: 138
    Thank you both...

    Thanks for your input... Hopefully the BTU rating of my boiler will come in on the wall-hung variety and I'll put the other items on pavers. Thanks - Jay
  • SWEI
    SWEI Member Posts: 7,356
    Lochinvar Wall Hung

    WHN or WHP models have a better HX design than the older floor mount models.

    Unless your house is over 12,000 square feet, they should have a model which will work.  Even if it is, two WHN's ganged together will give you a higher turndown ratio and some redundancy as compared to a single KBN.
  • Charlie from wmass
    Charlie from wmass Member Posts: 4,322
    Depends on where you are located

    In Massachusetts I have always been taught it needs to be a poured slab to meet code. Yes this goes for oil tanks too, despite people always using 4 cinder blocks.

    Vibration from the boiler can over time drive one block in more than the others. If the slab is one piece it should in theory all sink together if at all.
    Cost is what you spend , value is what you get.

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