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Furnace CFM

Jon_blaney Member Posts: 318
Why are the cfm ratings different for ecm and psc blower motors for the same furnace ?


  • Jamie Hall
    Jamie Hall Member Posts: 23,456
    It would be more remarkable if they weren't different, since every blower wheel and motor combination has different characteristics...
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Ironman
    Ironman Member Posts: 7,379
    ECMs maintain constant torque until they approach their rated horsepower, PSC motors don't. In fact, each speed tap on a PSC motor is actually a horsepower tap. If you run the motor without the wheel, it will go to full speed on any tap.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.