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Circulators in series...good idea or bad??

Big Ed
Big Ed Member Posts: 1,117
Just for lack of extra wiring most would keep them at the same location . Near and pumping away from the expantion tank is best. Trying to think if any side effect one being on the other side of the loop????

Installing them in series is used for head resistance. Side by side increases the volume of flow...

What pipe size ? What BTU out put?


  • Brian_18
    Brian_18 Member Posts: 94

    I'm planning my next year's DIY project. "Alternative" fuel (yet to be determined) boiler that will serve both my house and shop building. The location for the boiler will be 210ft. from my house, connected by underground insulated Pex, tied in to my house with a plate HX as a secondary circuit from my pri/sec house setup. My question is this: due to the distance, does it make any sense at all to have one circulator pump at the remote boiler (pushing to the house), and a second one in the basement (pushing back to the boiler)? Or, is it best to size one big pump to handle the head and flow by itself? I've had difficulty finding info on this topic, maybe because it's not generally done, or not a good idea. I'd like to hear from you folks. Thanks
  • Terry
    Terry Member Posts: 186
    1 pump

    I've never used anopther pump to "push" back to boiler.

    1 Pump s/b sufficient as long as it's sized to accomodate flow & head requirements.

    IF your alt boiler is an "Open System" - be careful selecting the pump as a lot of pumps have a Minimum INLET Pressure (the boiler may also be "raised" to increase inlet pressure on pump)

    just my 0.02
  • Joe Mattiello_2
    Joe Mattiello_2 Member Posts: 94
    Install pump in series on supply side of open system

    Pumping in series doubles the head approximately, and the flow stays the same. If it’s truly an open system both pumps should be on the supply close to the reservoir with the centerline of the pump shaft below the reservoir increasing the static pressure on the pump to help satisfy the pumps NPSHR. Always remember we only have atmospheric pressure to work with on the suction side of the pump in an open system. If you place one pump on the return, the probability of that pump cavitating would be very high. Additionally, the materials of construction have to be suitable for open system with all wetted parts non ferrous.

    Joe Mattiello
    Technical Support Technician
    Tel. 401-942-8000 X 484
    Fax. 401-942-2360
    1160 Cranston St
    Cranston, RI 02920
    [email protected]
  • JackFre
    JackFre Member Posts: 225
    how big is your shop?

    What is the heat loss? Even with an insulated, waterproof pipe system it doesn't seem to be a good idea. I can't see the advantage when you can put a small system in the shop and not have to mess with the underground. Trenching, waterproofing, backfill material, expansion loops, cost, heat loss (even in water tight/insulated), time, hassle...and hope it works right. Good luck with it, but I'd suggest going about it another way!
  • Marty
    Marty Member Posts: 109

    I would tend to agree with Jack. Another way to do it would be one pump sized for a loop out to the shop and back, pair of close spaced t's in the shop with a second pump sized for the shop alone. for what a couple hundred feet of ecoflex costs another solution may be better.
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