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Help with Blower Motor Please

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  • Help with Blower Motor Please

    Hi - I hope someone is more knowledgeable than me in reading and understanding wiring diagrams!

    I have a EMERSON Motor - Model: K055TFN8713012B for my Coleman furnace. This was a replacement motor as the other one died! The motor techs can be seen here - (you may have to search on their catalog for it) --

    My question is that when the motor was connected, I am not sure it was connected properly, as the wire diagram does not match the connections. What I am trying to do is speed up the motor.... There are three different wires for this - Black (hi) , Blue (med), and Red (low). The wiring diagram is here - -

    Long story short is that the tech told me I could hook up the black, blue or Red to the Brown wire that comes from the capacitor. This does not appear to work. :wall:

    The way it is hooked up now is that the black is actually connected to a wire that goes to the furnace wires (as is the white). The brown is hooked up from the capacitor to the motor. Also connected to the capacitor is a brown w/white stripe wire that goes to the motor. The blue and red are not connected on one end. So my question is, where should the black wire be connected (to the brown wire as the tech said?), and what if I want the Red or blue speed - where do they connect? The Coleman furnace model is 7710-856 (BTU in 95000/BTU out 72000), SN 048365484.

    Thanks for any help!!!!!!

  • #2
    Re: Help with Blower Motor Please

    Best to call or E-mail the motor manufacturer and talk to their technical people.
    Why do you want the motor to run faster?


    • #3
      Re: Help with Blower Motor Please

      First off, This motor you show with the link is a 240v motor. Are you sure your air handler is set up for a 240v motor? If yes go to next.

      You should have 2 wires that you removed from your old motor that come in from the electrical supply. They may be 2 blacks or a whitle and black, or maybe a black and red. No difference, they are both 1/2 of the 240 so makes no difference. The motor should have 2 "fast on" connectors as shown in the diagram, those 2 go to the capacitor. Then you connect one wire from your supply (any one) to the white. The other wire goes to any one of the Balck, Blue, or brown. Connect to black, motor turns fast, Blue medium, and red, slow. If this motoer is being used in a heating system you DO NOT want it to turn fast. Either med or slow for heating, but NOT fast. Thats it....Lou


      • #4
        Re: Help with Blower Motor Please

        Thanks for the help. It is a 115v motor. Does the speed make a difference in my outcome. In other words, I am thinking the higher the speed, the more the output of hot air. Any ideas? Also, does direction of the blower wheel make a difference? Thanks!
        Last edited by atvguy64; 02-01-2008, 10:11 PM.


        • #5
          Re: Help with Blower Motor Please

          The wiring diagram you linked to is for a 240 volt motor not a 115 volt motor, so either you have the wrong diagram or the wrong motor.

          Also, yes the speed does matter. If the speed is turned up to high, the furnace does not have a chance to prtoperly heat the air going through it so it basically ends up blowing cool or luke warm air. In the end, it will be a negative impact.



          • #6
            Re: Help with Blower Motor Please

            If your supply voltage to the air handler is 115V, then the diagram you have shown is the wrong motor. You show a diagram of a 240v motor not a 115v motor. So if that is the motor you have, you need to return it and get a 115v motor. Yes, the direction of the motor does make a difference, and the speed needs to be med or slow but not fast for heat. For AC the faster the better. Lou


            • #7
              Re: Help with Blower Motor Please

              Im a new member so I'll throw in me 2 cents worth. Yes, diagram clearly reads 208/240 volts. Please make sure you have the correct voltage motor for your furnace. Next item, capacitor (7.5 mfd.) is wired ONLY to brown and brown/white. White goes to your neutral (line) and red OR blue OR yellow OR black will connect to the hot side of the line. In heating the red OR blue will probably be the best speeds. Red is low, blue medium low, yellow medium high and black is high speed. Black is generally used for cooling only. Be sure to insulate unused leads as they will have voltage from back emf. As noted in a previous post, high speed in heat may blow cooler air. Furnaces are furnished with a heat rise specification and changing blower speeds is the way to change the heat rise temperature.


              • #8
                Re: Help with Blower Motor Please

                I'll toss in my 1/2 cent worth. Replace the filter(s) with good ones and open up all supply registers and vacuum clean all return grills. This needs to be done with power off for obvious reasons. Then get a good clamp-on Ammeter and try connecting up the motor at different speeds (Only after you're sure it is the correct replacement) and note the running current drawn by the motor. In some installations you can't run the motor at the highest speed without overloading it. For heating you normally would use low or med low. To be sure you would need to measure temperature rise if able. Normally med-low is preferred as you do need to move air, but at too high a velocity it won't feel warm to you, and you'll get more noise as well.