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  1. #53
    Join Date
    Dec 2007
    Posts
    4,670
    getting to the point of too much info for this section.

    I will say reread your diagram and see the bottom of the chart where it lists what they mean by number and color coordination.

    some units have different speeds on the motor due to size.

    also, motor dependent, the brown wire, FROM THE MOTOR, is usually connected to the capacitor. this does sometimes vary by mfr/tech knowledge.

    as for connections at the board, read the schematic to see where the motor wires should land/connect. there are specific places to connect for heat(H) and cool(C) speeds. you only use the jumper if you are using the same speed for both heat and cool, which you unit does NOT call for.

    sounds like you have a grasp on the concepts, so take a few minutes, read the schematic/diagram, trace the motor wires, determine the motor installed(if possible) and see if things match up. if not, your issue is the motor. I would say it is the motor since the issue happened after the change, but there could be other things that caused the original motor to fail in the first place.

    put the panel back on the evap coil(is the coil dirty or blocked with hair, lint, etc? if so clean it) and proceed from there. it needs to be in place to direct the air in the proper pathway.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  2. #54
    Thank you for the input.

    I am assuming that the black and white wires are where they are supposed to be. I looked at the circuit board again and I don't see any jumper locations that look like the terminals described in the notes on the diagram. Maybe that is what confused the tech?

    Anyway, if the red wire should not be connected then it was not done correctly.

    I think that you may be correct that the unused wires are simply bound together and the ends have electrical tape wrapped around them. I doubt that they are electrically connected or he would have used a connector. The tape is probably just to prevent a short if the end contacted something.

    It sounds like he just connected the wrong wire.

    I will call them back in. I paid them to do it right, so hopefully they will get this done correctly. I will also ask to ensure that it is a 1/2 HP motor with 1075 RPM. Is there anything else that I need to check regarding the motor? I .E. CFM ratings?

  3. #55
    Join Date
    Dec 2007
    Posts
    4,670
    how many wires on the new motor and what color are they, unless you have the information from the motor?

    post a close up photo of the control board where the motor wires connect, colored ones as white should go next to more white/neutrals.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  4. #56
    There are 6 lead wires coming off of the motor plus two wires connected to the cap.

    The wires connected to the cap are purple.

    The blue, yellow and brown wires are bundled and not used.

    The red, black and white wires are connected to the circuit board.

    I will send images of the circuit board next.

  5. #57
    Here are four images of the board. One close up of the board and one each showing the red, white and black wire locations.Name:  Board Close up.jpg
Views: 95
Size:  59.0 KBName:  Motor Black Wire on Board.jpg
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Size:  64.9 KBName:  Motor Red Wire on board.jpg
Views: 106
Size:  66.7 KBName:  Motor White wire on board.jpg
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Size:  63.5 KB

  6. #58
    Join Date
    Dec 2007
    Posts
    4,670
    Quote Originally Posted by jimdavisjr View Post
    There are 6 lead wires coming off of the motor plus two wires connected to the cap.

    The wires connected to the cap are purple.

    The blue, yellow and brown wires are bundled and not used.

    The red, black and white wires are connected to the circuit board.

    I will send images of the circuit board next.
    sounds like the correct number of wires/speeds on the motor and except for the red wire, all connected properly.

    red should be removed and yellow put in its place- per mfr schematic.

    only question is 1/2HP motor or not.
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  7. #59
    Thank you.

    Though this fix seems easy enough, I will still call the local company back to make this change. I don't want to screw it up and not have it covered by whatever warranty it might have. I will ask them to advise me of the HP on the motor that they used when I call them. If it moves enough air to prevent cycling after they rewire it, is there a big problem if it is 1/3 HP vs. 1/2 HP? I suspect that the smaller one would have to work harder and wear out faster. Are there any other specs that are important on the motor ... i.e. CFM or RPM? Or is checking the HP good enough?

  8. #60
    Join Date
    Dec 2007
    Posts
    4,670
    call them back, it should NOT cost you anything as it is incorrectly done.

    have the speed changed and have them do a temp rise calculation and see that it is within the mfr specs listed on the data plate(45-75), where you pulled the model number from.

    1/2 HP, 1075 RPM, 115V
    The Food Stamp Program, administered by the U.S. Department of Agriculture, is proud to be distributing the greatest amount of free meals and stamps EVER.
    Meanwhile, the National Park Service, administered by the U.S. Department of the Interior, asks us to "Please Do Not Feed the Animals". Their stated reason for this policy "... the animals become dependent on handouts and will not learn to take care of themselves."
    from an excerpt by Paul Jacob in Sun City, AZ

  9. #61
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,158
    Depending on the size of your AC an incorrect motor may not provide enough airflow for proper cooling.

  10. #62
    Join Date
    Jun 2005
    Location
    SW Wisconsin
    Posts
    4,897
    Quote Originally Posted by jimdavisjr View Post
    Thank you.

    Though this fix seems easy enough, I will still call the local company back to make this change. I don't want to screw it up and not have it covered by whatever warranty it might have. I will ask them to advise me of the HP on the motor that they used when I call them. If it moves enough air to prevent cycling after they rewire it, is there a big problem if it is 1/3 HP vs. 1/2 HP? I suspect that the smaller one would have to work harder and wear out faster. Are there any other specs that are important on the motor ... i.e. CFM or RPM? Or is checking the HP good enough?
    I Got the furnace specs.
    That 125 number is the Input, not the Output on that Lennox Brand of equipment.

    Usually a 1/2-HP motor won't quite deliver 1400-CFM; marginal HP even at .50" ESP. CFM if the furnace output is 100,000-Btuh Output.

    Listed Temp-rise is 45-65-F. | using Max 65-F temp-rise * 1.1 is 71.5; 100,000-Btuh / 71.5 is 1398.6-CFM or, I'd say, 1400-CFM. However, the duct system will probably be will above .50" ESP lowering the CFM.

    With your duct system & filter, It would need the jumper to run on the high speed in heating mode; unless cooling mode could use a lower speed.

    Make sure they check the wiring of the capacitor...

    Blower data: I believe that model calls for a 3/4-HP motor which would deliver 1405-CFM at .70" ESP; which I'm betting your duct system would have.

    Just my tentative view of the situation from here...

  11. #63
    Join Date
    Mar 2005
    Location
    burlington county n.j.
    Posts
    9,709
    3/4 ton blower package uses a 1/2 hp motor.
    original motor was a leadless motor with the plug at the motor where speed selections were made.
    only wires coming from motor to blower control board were white , black and red.
    when a replacement motor is used you can either run the new leads up to the board if long enough or splice them to the originals if needed.
    for a 125 furnace the red wire on the motor is the wrong one, i would go yellow or brown and check temp rise.
    capacitor laying in the bottom of blower section is just a sign of crap work ethics......

  12. #64
    Join Date
    Jun 2001
    Location
    Moore, Oklahoma, United States
    Posts
    4,158
    Quote Originally Posted by udarrell View Post
    I Got the furnace specs.
    That 125 number is the Input, not the Output on that Lennox Brand of equipment.

    Usually a 1/2-HP motor won't quite deliver 1400-CFM; marginal HP even at .50" ESP. CFM if the furnace output is 100,000-Btuh Output.

    Listed Temp-rise is 45-65-F. | using Max 65-F temp-rise * 1.1 is 71.5; 100,000-Btuh / 71.5 is 1398.6-CFM or, I'd say, 1400-CFM. However, the duct system will probably be will above .50" ESP lowering the CFM.

    With your duct system & filter, It would need the jumper to run on the high speed in heating mode; unless cooling mode could use a lower speed.

    Make sure they check the wiring of the capacitor...

    Blower data: I believe that model calls for a 3/4-HP motor which would deliver 1405-CFM at .70" ESP; which I'm betting your duct system would have.

    Just my tentative view of the situation from here...
    Is there any harm in running the blower on high for heat and cool? Do you see any risk of getting below the minimum 45f rise, even with a 3/4HP motor?

  13. #65
    Join Date
    Nov 2001
    Location
    east kansas
    Posts
    8,024
    Do you live north or south of Olathe?
    Beware of advice given by some guy on the Internet.

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