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Bosch aquastar 125NG

sleppydc Member Posts: 1
Does anybody have any experience with installing a bosch tankless water heater in a infloor heating system.  I Had a plumper install a aquastar 125 in my garage after I upgraded to a Rhinnia for hot water in my house. I didn't have another use for the unit so I figure I would try it in my garage floor I recently finished. The problem is the unit seems to only operate on a pressure drop with the water flow, and once all the air was bled out of the system the burner wouldn't kick on. The plumber thinks we need to install a larger pump on the outgoing side to create a suction to activate to switch to fire the burners.  The pump is going to run 300$; I think I might as well bag the idea of using the bosch but if anybody has any ideas I'll try it first.


  • kcopp
    kcopp Member Posts: 4,432
    Here we go.....

    again...... Another person trying to use a product Not designed for what it is supposed to be used for.  Ditch it. Get a  boiler. You will have nothing but problems.... and spend a lot of time and money trying to get the water heater to work and still not have it working the way a boiler will.
  • Jack
    Jack Member Posts: 1,047

    You will notice that Rinnai does not allow this application on their units. They have excellent technology in the flow control and gas valve control and it still would not work. Your aquastar has nowhere near the control of your Rinnai. You can keep throwing money at it, but you are building a headache and throwing good money after bad.
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