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  1. #1
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    Hall effect sensors

    Why/how is it I see a lot of these draft motors on rooftop units that have the wires cut to the hall effect sensor? Is this a way to bypass the sensor somehow? Units are still heating..

  2. #2
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    Quote Originally Posted by heatingelement View Post
    Why/how is it I see a lot of these draft motors on rooftop units that have the wires cut to the hall effect sensor? Is this a way to bypass the sensor somehow? Units are still heating..
    Carrier?

    Sent from my LG-G710 using Tapatalk

  3. #3
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    Quote Originally Posted by heatingelement View Post
    Why/how is it I see a lot of these draft motors on rooftop units that have the wires cut to the hall effect sensor? Is this a way to bypass the sensor somehow? Units are still heating..
    Are any of those wires spliced together? I did not think the unit would heat without that sensor properly plugged into the board.
    I do a triple evac with nitro to remove non condensables.

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  5. #4
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    Did you see a pressure switch ?

  6. #5
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    Quote Originally Posted by heatingelement View Post
    Why/how is it I see a lot of these draft motors on rooftop units that have the wires cut to the hall effect sensor? Is this a way to bypass the sensor somehow? Units are still heating..
    What is the model number?
    Instead of learning the tricks of the trade, learn the trade.

  7. #6
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    Emergency stairs?

    Hotel, Motel Common hallways?

  8. #7
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    Quote Originally Posted by rundawg View Post
    What is the model number?
    I suspect either pre or post hall effects sensors used by Carrier.

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  10. #8
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    Thread Starter
    Yes, carriers. I didn't look into them or grab the models. Just came to me as an after thought. Next time I run into one, I'll look into it more.

  11. #9
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    Maybe someone picked up a motor with the Hall Effect and went to replace a motor with the two wire centrifugal switch. Couldn't figure it out, so installed the motor, cut the three wires to the plug, and wire nutted the two wires that went to the original motor's centrifugal switch.

    That could be a reasonable scenario, for a hack.

    On a bit of tangent:
    The first time I heard about a Hall Effect Transistor, yes, that's what they called it when I first heard about it, was in something like a Popular Mechanics. Can't remember for sure. Might have even been Scientific American. Any way, the article was extremely interesting to me.

    They were describing how the heart beat of a fly was measured with one.

    I'm guessing the basic [theoretical] concept of the sensors on the induced draft motors of today use the same principles of those original "transistors". But are probably much less sensitive, much more cost effective, and could never measure the heart beat of a fly.

    But, you have to admit, it is very interesting when our scientists/researchers take things like this to the extreme.
    I do a triple evac with nitro to remove non condensables.

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  13. #10
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    Pull the power to inducer while running in heat and verify it shuts down, if it does must be a pressure switch in it somewhere. At the least verify shut down on failed inducer!
    UA Local 32 retired as of Jan 2020

  14. #11
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    Quote Originally Posted by VTP99 View Post
    I suspect either pre or post hall effects sensors used by Carrier.
    are you saying that newer carrier boards didn’t require the sensors, yet the inducer fans were never changed to meet the new board requirements?

    This post is another prime example of needing some model numbers. Not being a dick, just making an observation. Causes a lot of speculation.

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