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Biological control for filler station

MatthewPK
MatthewPK Member Posts: 22

I have a filler station attached to my closed loop system. Since this is seasonal and the radiant loops run lower temperature the water in the filler station is stagnant.

Should I be using something else in the filler station? Perhaps I need to add a biocide agent?

Comments

  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 10,914
    edited September 4

    On a closed system there is no need for bio control in most cases.

    If you are using your potable hot water heater for heating both the water you shower with and the floor heat, then stop doing that. There will be bio hazard issues that you don't want to have near you in the shower or the kitchen. Your closed loop system and your Domestic Hot Water (DHW) need to be two separate systems.

    What is a filler station?

    Edward Young Retired

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

    MatthewPKMad Dog_2
  • MatthewPK
    MatthewPK Member Posts: 22

    My boiler is in a utility room without easy access to make-up water so it's setup with a digital fill station. Specifically the DMF150 https://axiomind.com/axiom_product/dmf150/

    This replaces a pressure-regulated valve at the fill port.

    So as air is purged or sediment is flushed, or pressure relief valves drip etc the system pressure is maintained.

    This water is never heated.

  • MatthewPK
    MatthewPK Member Posts: 22

    Also, side note, these are very useful for leak detection because you can easily tell if if it's pumping from its tank into your system.

  • hot_rod
    hot_rod Member Posts: 25,543

    if it is plain water those fill tanks are open systems. You may need to add a shot of chlorine from time to time

    Is it well water or public water?. Well water probably doesn't get chlorinated.

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
    EdTheHeaterMan
  • MatthewPK
    MatthewPK Member Posts: 22

    I filled with municipal water. It's easy enough to add chlorine to it but I wasn't sure if chlorine would cause problems in the system.

  • Jamie Hall
    Jamie Hall Member Posts: 26,299

    Chlorine won't be a problem. Chloride — note the spelling difference — would be.

    Any set up like that I would want to see either an air gap or a reduced pressure zone backflow preventer separating it from the domestic water supply — whether it's municipal or well.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • MatthewPK
    MatthewPK Member Posts: 22

    Please don't take this the wrong way but info I find online seems to strongly discourage adding chlorine to radiant boiler systems.

    Here's Google, for example (I know, I know.. AI...)

    1000002743.png
  • Jamie Hall
    Jamie Hall Member Posts: 26,299

    Ah yes. Google knows everything… don't mind us.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Mad Dog_2
  • MatthewPK
    MatthewPK Member Posts: 22

    I know you guys are the pros :) that's why I come here.

    Is there anything you suggest I read to learn more about what sort of biocides are safe to use versus not? Is there a particular chlorine product that you like for this use case?

  • Jamie Hall
    Jamie Hall Member Posts: 26,299

    I would use a straight chlorine bleach, such as Clorox. BUT. You don't need much. The concentration of bleach you are shooting for is between 1 and 5 mg/l. Now that's not much help, is it? Simple translation: you need (more or less) about 3 parts of liquid bleach to 1,000 parts of water. It's a simple ratio.

    So, for example, if your system volume of water is around 20 gallons, you need to add 0.06 gallons — or about 1 cup of bleach. It will need to be mixed thoroughly in the system.

    That, incidentally, is also the concentration of chlorine in public drinking water. So if you are on a municipal or other public system, it's already there unless you have aerated the water or distilled it — or have an activated carbon filter.

    It will, however, gradually leave an open container. It will NOT leave a closed system, even when heated, but if there is significant organic matter in the water, it will be used up by breaking that down.

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    MatthewPK
  • hot_rod
    hot_rod Member Posts: 25,543

    a lot of the water providers use chloramine now instead of chlorine it stays in the water longer, for situations like you have.

    Put a UV bulb in it. Maybe Axiom should condider that😏

    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Jamie Hall
    Jamie Hall Member Posts: 26,299

    Yes, chloramine is very common. Has some real advantages, but… its not something the ordinary Joe can go to a store and buy, and certainly not something to make on site! So… bleach.

    I might note in passing that the suggested concentration is a lot lower than a swimming pool. But swimming pools have contamination problems which folks don't like to mention but surely do exist!

    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
    Mad Dog_2
  • MatthewPK
    MatthewPK Member Posts: 22

    Thanks for the advice, gents!

    Should I be concerned about any additives interacting with the chlorine? (Like 8-way or Hercules, etc?)

  • pecmsg
    pecmsg Member Posts: 6,418

    How often to you add water to this system?

  • hot_rod
    hot_rod Member Posts: 25,543

    I have not heard of any issues with algae or bacteria growth in those stagnate fill tank systems? Have you?

    You might call Axiom directly ask for Kirk, Alan or Ian they would certainly know this by now after all the years of building those systems.

    Screenshot 2025-09-05 at 8.11.15 AM.png
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • pecmsg
    pecmsg Member Posts: 6,418

    then it’s not a concern

    MatthewPK