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  1. SASSAFRASS

    Sizing a water system pressure pump

    Not always, but sometimes a suction riser in the line before the pump can help nuisance priming issues when you can't get head on the pump suction. Using the self vulcanizing rescue tape on tiny vacuum leaks in fittings will help too.  Vacuum leaks are a major pain, used to run a ancient 200ton...
  2. SASSAFRASS

    Sizing a water system pressure pump

    If you have a decent strainer in the system, you can remove the sediment screen in the shower head, usually makes a difference by increase in flow. If you have a household mixing valve same thing can really restrict initial flow. Sure you already know but line size on these is huge, going up on...
  3. SASSAFRASS

    Sizing a water system pressure pump

    ^ On a high pressure setup yes it's tricky, IE thousand of PSI but on a positive displacement pump at low pressure no, you shouldn't see a significant spike.  A good logic loop or PID will spool up and down as the target is required and approached over a time factor. A practical example would...
  4. SASSAFRASS

    Sizing a water system pressure pump

    The marco pumps can run at fairly high pressure.  With a decent PID built into the logic and some sort of hysterisis you don't need a accumulator. It's going to come on spool up slow to meet pressure and have a differential to eliminate short cycling.  This is super common in industrial process...
  5. SASSAFRASS

    Sizing a water system pressure pump

    The Johnson above was $4k so two of the Marcos at $1k ea was a great deal!
  6. SASSAFRASS

    Sizing a water system pressure pump

    I speced two of the 12 gpm pumps to replace a 25gpm Johnson, I think it was a repackaged ind pump, huge 24v dc.  They have been able to just run one of the marco pumps with great performance.  If we need to replace our Johnson diaphragm I will go to the Marco.
  7. SASSAFRASS

    Sizing a water system pressure pump

    Fisheries supply in Seattle sells them but you can buy direct.
  8. SASSAFRASS

    Sizing a water system pressure pump

    Check out the company in Florida with the composite gear pumps, Marine or Mariner mate something.  I helped a friend spec two to replace a huge johnson pump setup on a big sailboat.  I think it's a variable speed pump with a simple processor.  Accumulator setup will fail period.  The diaphragm...
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