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adding one small pump to a gravity-fed system

I have a open gravity-fed hot water system in my two-story house in central New York state.  All the radiators are on the first and second floors, and there's an expansion tank near the ceiling on the second floor. 

I have a small finished bedroom in the basement that currently has electric baseboard heat, but I'd like to heat it using the boiler and hot water.  The problem is that the room is no higher than the boiler, so gravity won't move the water to and from a typical radiator.  (The room is safely separated from the boiler by a rock and cement wall though.)

One option I see is to buy a used ceiling-mounted radiator.  I wonder though whether this will keep me warm enough in my bed since heat rises.

Another option is to use a normal floor-mounted radiator and install a small low-flow pump just to circulate water through this branch of the hot water system.  Do such pumps exist?  If so, what are some brand names and where could I buy one?

I'd rather not add a pump to the entire system because I like the simplicity of the system and that all it needs is 24 volts to run the thermostat.

Any advice would be most appreciated.


  • icesailor
    icesailor Member Posts: 7,265
    Gravity System:

    You will probably never do this but if you asked me and you were serious about doing it, I would suggest that there are no guarantees that it will work.That said:

    Find a copy of the Slant-Fin heat loss guide and do a careful and accurate heat loss on your house as it would have been done when the house was build. That means no insulation. Do the cellar room as a separate item. Get some copy of a book with the listings of all new and old radiators. You can get the #250 Advanced Installation Guide for Hydronic Heating Systems from the GAMA/IBR. Take the BTU heat loss of each room and compare it to the EDR of the radiators in the room. Do all the rooms and look for some pattern that the old dead guys used to come up with the amount of radiation in each room. Average it out in what way you can. Compare this averaged out number with what you need in the cellar room. Cut into the piping and put a circulator in it to heat the cellar zone. It isn't perfect but it will work.

    This IS a gravity system with no pump isn't it? That's why you are concerned about piping down?

    The biggest problem I see to this is where and how are you going to cut into the system.

    Good Luck,
  • MrKit
    MrKit Member Posts: 2

    Ha, that sounds like some work!  On the other hand, it is methodical.  Could you please provide a little more information about the circulator you mention.  Specs, brand, and maybe a link?

    Yes, it is gravity-fed, and that's why I'm thinking about this fix.  Thanks for your help.
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