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Blower and HP?

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  • Blower and HP?

    I am heating with an alternate fuel furnace and the fall changed out my direct drive blower for a belt drive. The reaso, it is quieter.
    My question is how should I determine if I need amore powerful motor,I used a 1/3 hp because I had it.
    Since a lot of this is trial and error I have also been playing around with pulley sizes.
    But my question is really about the HP.

  • #2
    Re: Blower and HP?

    If it is only for heat your question is simpler...

    If you are getting enough air through the system to keep it from tripping out on a temp limit you are ok

    Really though the heat exchanger or system you have installed should have a temperature rise / delta (Outlet air temp - inlet air temperature)
    associated with it. So too little air will give you too high of a delta and too much air will give you too low of a delta.

    If you just want to match Rpm's of the old direct drive system input your info here and this will do the math for you... If you can't hit the target RPM you need while keeping your motor at it's rated amperage you will need to increase the size of your motor.

    Last edited by OkieBill; 12-11-2009, 09:08 PM.


    • #3
      Re: Blower and HP?

      Split Phase capacitor run blower motor;
      I had an instructor that thought the blower motor speed selection should be called wattage selection. I liked that since in some situations the only thing that really changed was power consumption. Temperature rise & rpm was basically unchanged.
      Retired HVAC tech, Dennis.....