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Gravity system - pump help

MichaelT
MichaelT Member Posts: 26

hello, I have a radiant floor heat system that for the previous couple winters has struggled due to a leak in the old rubber tubing that we have been unable to find. To combat this - we put a 15 gallon tank in our attic with a float to fill up the tank more if the fluid runs low. But with the system no longer being pressurized the taco pump 0011-F4 wasn’t getting enough flow to fire up the system well. So I installed a small transfer pump right after the 15 gallon tank to supply some pressure to the taco pump which is 20-25 feet away. That worked but the transfer pumps are not lasting. And I know they are meant for continuous use. Does anyone have any recommendations on which pump to use right after the 15 gallon tank? Can a taco pump run on just a gravity feed? I’m thinking to put a 007 taco right after the tank instead of the transfer pump but not sure if it will work

Comments

  • mattmia2
    mattmia2 Member Posts: 11,029

    Axiom makes packaged feed pumps that are made for feeding make up water in to hydronic systems but if the tubing is failing this is just a band aid.

  • hot_rod
    hot_rod Member Posts: 23,507

    how fast of a leak? Adding a lot of fresh water will scale everything up

    Did you try a leak sealer? I have had mixed results with Fernox LS1

    It just depends on the size if the hole or tear

    Is it RadiantRoll, 5/16” diameter tube? Or a larger diameter Heatway/ Watts tube? Or other?

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    GGross
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 9,526

    Somehow I don't see this as a gravity system as I know them. Gravity systems have no pumps. and really big radiators.

    Maybe a true gravity system can solve the problem. Lots of large pipes and big radiators, maybe even an old coal boiler in the basement. That way you abandon the leaking floor tubing.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?

    GGrossdelcrossv
  • GGross
    GGross Member Posts: 1,322

    Pretty much all of your components are most likely designed to function in a sealed system. Boiler "pumps" while referred to as "pumps" are actually circulators, they don't pump like a sump pump or the like. You went to a lot of trouble to mask the leak, there is a good chance you are building up sludge from all the metal components rotting out from fresh water being constantly added. There are ways to automatically maintain a systems set pressure via fill valve, this will still destroy the ferrous metal components in your system over time. There are packaged filling units that do exactly what you need, you can fill them with DI water to control the quality of the fill fluid but the unit will need to be manually filled or it will run empty

  • delcrossv
    delcrossv Member Posts: 1,437

    Do yourself a favor and abandon the radiant. Plumb in another radiator for that room.

    Trying to squeeze the best out of a Weil-McLain JB-5 running a 1912 1 pipe system.
  • MichaelT
    MichaelT Member Posts: 26

    I did try a leak sealer called GeoLoop but it sadly did not work. I wonder if Fernox LS1 would work better. The tubing is definitely non-oxygen barrier rated. It is a black rubber that I believe is Watts. Seems to be about 1/4 inch tubing.

  • MichaelT
    MichaelT Member Posts: 26

    I know, all of the components are designed for a sealed system. And this really is not ideal. I'm mainly trying to get it to last for this winter to prevent freezing in a car wash bay.

    The leak is underground in the concrete. Using a IR camera I've still been unable to find it.