Boilermate and Gravity Recirculation

Discussion in 'Water Heater Forum, Tanks' started by In_Maine, Mar 20, 2013.

  1. In_Maine

    In_Maine New Member

    Messages:
    2
    Location:
    Maine
    Has anyone installed a gravity recirculation loop with a Boilermate?

    I have a 40 gallon boilermate that has the dcw inlet on the bottom and the dhw comes off the top. The only other connections are the supply and return to the boiler.

    I want to add a return loop from the farthest fixture to the boilermate. I am assuming I would "T" into the dcw supply at the bottom of the boilermate, with a check valve to prevent cold water from traveling along this return loop.

    Should there also be a check valve on the dcw line to prevent warm/hot water from migrating into the cold water line?

    Any advice is appreciated...I just am not interested in a solution that requires a pump, please.
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,892
    Location:
    New England
    The return line needs to be laid out properly and installed properly for a gravity recirc system to work. Any jogs that take that line up again will stop the flow. There is very little difference in density of the water at the temperature extremes so it doesn't take much to stop it in the return loop. It doesnt' need much of a pump, but that pump must be either SS or bronze since it is potable water, so that makes it on the expensive side. Operation of say a 1/30Hp pump isn't very much and can be reduced if you put it on a timer so it doesn't run when you have little expectation of needing fast hot water.
  3. In_Maine

    In_Maine New Member

    Messages:
    2
    Location:
    Maine
    Thanks for the info.
    What do you mean by "Laid out properly and installed properly"?
    I should have a pretty ideal set up for gravity. The return line will only slope down towards the Boilermate with no jogs or "U"s, etc.
    Pump would be a last resort.

    Any thoughts on how/where to connect the return line to the boilermate considering the it only has a CW in and a HW out? I am inclined to believe that the loop return would have to be connected to the CW in line, and I am assuming that I would need a check valve before it connects to the CW in. Would I also need a check valve on the CW inlet side as well?

    Thank you again.
  4. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    21,892
    Location:
    New England
    The difference in density of water at various temperatures is measurable, but it's not much. So, it needs a 'smooth' path with no slope issues, or that will stop the convection loop. Yes, it needs a check valve, otherwise, when you ask for hot, it would flow from both the bottom (cold) and top (hot) parts of the tank. One on the return line should be fine.
Similar Threads: Boilermate Gravity
Forum Title Date
Water Heater Forum, Tanks Boilermate temps fluctuating Mar 26, 2013
Water Heater Forum, Tanks Gravity recirc stopped working Jul 14, 2014

Share This Page