• PlutoniumAcid@lemmy.world
    link
    fedilink
    English
    arrow-up
    1
    ·
    7 days ago

    I don’t fully understand how this works. The pump and valve are used to circulate hot water though the hot pipe and back through the cold pipe.

    But… doesn’t that mean you never have cold water? Because the cold pipe is by definition also hot now?

    It seems as if this just shifts the problem from “wasting hot” to “wasting cold” to get the water you want.

    • CompactFlax@discuss.tchncs.de
      link
      fedilink
      English
      arrow-up
      2
      ·
      7 days ago

      Yeah it’s confusing.

      When the hot side of the valve is cold, the valve opens. When it’s hot, it closes. The pump pushes the cold water on the hot side through until warm water reaches the valve, then it closes, and the pump can just keep going without moving any water. As the water at the valve cools down again, the valve opens again.

      With an aerator on the tap it’s not much more than a second of warm water so the wasted water isn’t really much volume at all - 100mL vs several litres. I also have a separate drinking water tap which is really my only cold water application so a bit of water at 30° instead of 18° doesn’t bother me.

      • PlutoniumAcid@lemmy.world
        link
        fedilink
        English
        arrow-up
        1
        ·
        6 days ago

        Thank you Flax, this was a very useful explanation! I will look into it and figure whether I can install it in a suitable place in my bathroom.

    • JordanZ@lemmy.world
      link
      fedilink
      English
      arrow-up
      2
      ·
      7 days ago

      Not the original person but I’ve looked into these. The answer is yes. The draw back to that type of system is if you want plain cold water then you’ll need to get through the luke warm water first.

      Most houses have many loops of water pipes. So you’d want to put the valve somewhere you desire hot water more than cold. I find bathrooms would be more useful than the kitchen. Less wasted water when hopping in the shower, washing hands, or if you have a bidet (even just a cheap cold water one it would now be warm for awhile). In a kitchen it’s more ambiguous. I fill pots with cold water for cooking more than I probably want hot water for the dishwasher. Having not had a system like this personally I’m not sure if filling up a pot of water getting an initial charge of warm would really be noticeable though.