Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

Old Gravity Hot Water System

JRG Member Posts: 2
Wanted to start by thanking everyone here, I have learned quite a bit from this site, and I appriate it very much. I'm in the process of making an offer on a house that has an old gravity fed hot water system. The boiler is probably 1930 or so, when the house was built. I know I need to replace the boiler since it is VERY inefficient and it smokes a bit. I'd like to know if replacing just the boiler is a waste of time/money. Should I just scrap the entire system and start over with circulators and baseboard? Don't really want to spend the $, but I don't want insufficient heating either... Any advice? If I leave the boiler at a constant temp, should the system heat alright? Also, I think it's one of those funky ones with no expansion tank... Can't find it anywhere.


  • Ted_9
    Ted_9 Member Posts: 1,718

    A professional can replace the boiler with some piping changes and give you a modern efficient heating system.


    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
  • Tharon
    Tharon Member Posts: 26

    ME with TED scrape the boiler rework the near boiler piping, and properly done you will have a world class system. Ready for the next thirty years. Best Wishes J.Lockard
  • Steamhead
    Steamhead Member Posts: 16,719
    I have a system like that

    and it works great. Those big old radiators are way more comfortable than fin-tube baseboard.

    The biggest mistake I see with these old systems is over-pumping them. There is so little resistance in those big old pipes that it's way too easy to move the water fast enough that it doesn't have time to pick up heat in the boiler or shed it in the radiators. You need to know how many square feet EDR of radiation you have- you can find radiator charts in Dan's book "E.D.R.", available on the books and more page of this site. Then you or your contractor can use the chart at the link below to get the proper flow rate, which will determine the proper circulator to use:


    Size the new boiler to the house's heat loss, not the amount of EDR you have. The boiler temperature will vary with the heating load, especially if you use outdoor reset. And a new expansion tank can be installed in the basement. Lastly, the boiler should be piped to "pump away" from the expansion tank and air separator. This will keep the radiators from filling with air.

    There are many good boilers out there, the best choice is likely the one that your contractor is familiar with. And speaking of contractors, you can find many good ones on the Find a Professional page of this site.

    To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"
    All Steamed Up, Inc.
    Towson, MD, USA
    Steam, Vapor & Hot-Water Heating Specialists
    Oil & Gas Burner Service
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    As long as you can deal with the physical presence of the radiators, keep both the radiators and their associated piping. Don't cover them!

    For the cost of scrapping and replacing you can likely rejuvenate your old Cadillac with thermostatic radiator valves and a condensing, modulating boiler. Rather doubtful that the replacement boiler will last anywhere near 70+ years, but one of the finest quality [might] approach half that time with reasonable maintenance. Your fuel consumption will make a nosedive and your comfort will be as good or better than current.
This discussion has been closed.