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Gravity hot water system and condensing boilers

Scott McGuire
Scott McGuire Member Posts: 21
in THE MAIN WALL
I have a job that has an old gravity heating system. The owner wants to install modern gas fired condensing boiler to the system. I am looking for any thoughts on doing this type of installation. I feel it would be fine as condensing boilers love cold water return temps but was wondering how it would be piped. The old boiler has two 3 inch supplies and two 2 1/2 returns. Any one have any thoughts or experience with this type of set up.

Comments

  • Zman
    Zman Member Posts: 7,611
    condensing will work

    You have a great application for a condensing boiler. Be sure to pipe it primary/secondary. You will need to reduce the size of you near boiler piping to somewhere around 1 1/4" to 1 1/2" this will give your circs something to push against. Also be careful not to over pump the radiators, they will perform best at their designed flow rate. Outdoor reset is of course essential.

    I would recommend buying "classic hydronics" from this site. It is inexpensive and will tell you all you need to know.
    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • Scott McGuire
    Scott McGuire Member Posts: 21
    Reply

    Thanks for your advise. Will purchase the book to get further educated.



    Scott
  • Paul48
    Paul48 Member Posts: 4,469
    Proper

    sizing is critical. Do an accurate "heat loss", take care of any cold areas that already exist. Avoid micro-zones, and favor smaller over larger, in regards to boiler size.
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