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AO Smith Circulator Used For Heat Exchanger

Krash Member Posts: 10
My AO Smith 540 has a circulator pump, that is used used in conjunction with a return loop, to supply almost instant hot water to the fixtures. I want to know if this function would be appropriate to use as the circulation pump to my heat exchanger instead of buying a separate pump.



  • Jamie Hall
    Jamie Hall Member Posts: 22,114
    A pump is a pump is a pump... it is purely a question of can that particular pump deliver the flow you need through the total head loss of the circuit. You need that total head loss and you need the required flow, then you look at the characteristic curve for the pump and see if it will work.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Zman
    Zman Member Posts: 7,493
    Can you tell us a little more about the system?
    Is this the project? https://forum.heatinghelp.com/discussion/182313/should-manifold-be-on-second-floor#latest
    It looks like you are trying to convert a tankless water heater into a combi boiler. Are you wanting to use the DHW recirc pump to feed the heat exchanger?

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein