Is a buffer tank always better than a single tank?

Discussion in 'General Discussions' started by SomedayHouse, Jul 6, 2012.

  1. SomedayHouse

    SomedayHouse New Member

    Point #2 makes sense because non-electric water heaters heat the water using a 'burner' at the bottom of the tank.

    As ENGINEER has pointed out earlier in this thread, when the DSH is hooked up to a single water heater tank you turn the lower element to <100F (or even OFF) so that the DSH can heat up the lower 2/3's of the tank. Apparently this didn't happen in your case.

    While installing a buffer tank would be better, you can at least stop the bleeding by turning the lower element in your Marathon to the lowest setting, preferably <100F.

    Someday House
    Last edited: Jul 25, 2012
  2. TripleNickelSS

    TripleNickelSS New Member

    Ok, I follow you with the burner in non electric tanks - thank you.

    I'm not sure I follow the logic with the lower tstat being set low like this. You're still pushing "colder" water up to and past the upper heating element as the DSH cycles the water through the tank and back to the pump again, no?

    I actually have to turn both tstats past the 125 degree temp that we find to be comfortable, to get 125 degree water when the DSH is running. That's how I noticed the excessively hot water inbetween heating and cooling season.
  3. engineer

    engineer Well-Known Member Industry Professional Forum Leader

    If the bottom element is set for 100, then it has nearly always done the majority of the heating before the DSH gets a chance to do its thing.

    If the bottom element is off, the DSH can do its thing on the bottom 2/3rds of the tank. That works well until mild weather gives the DSH the day off, and the bottom 2/3 of the tank is not heated. That means that whoever takes shower number one has a good day, but showerers two and three get short shrift if the top element is toting the whole load.

    In short, don't bother buying the DSH option unless a buffer is included.
  4. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    No upflow

    Triple Nickel, you seem to be thinking cooler water will flow from DSH up through the tank. If tank is plumbed properly, the DSH return should be coming in the bottom drain valve and is drawn off to the DSH through the dip tube on the cold water fill side (near the bottom third of the tank). If set up properly, you oughtn't be pushing the DSH product all the way from bottom to top.
  5. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    There are many ways to plumb a DSH "properly".
  6. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    Many Ways

    While I wholeheartedly agree there are many ways to "properly" plumb a DSH, you do begin to run up against some practical restrictions if you are using a single powered tank with upper elements as your finishing stage as indicated in earlier posts.
  7. I have a customer that turns off his propane heater until he senses a lack of hot water. Generally only about two months a year.

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