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Thread: FANtastic

  1. #1
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    FANtastic

    Customer just bought a home a week ago, called about a loud furnace. Showed up and fired it on to listen to what was going on, didn't take long to figure it out. 5 ton Goodman from 2004, had a new blower motor in 2008. The board was like that when I took the doors off.
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  2. #2
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    Ain't got no time to re-mount the board after installing the high efficiency blower wheel shown in the photo's.
    I do a triple evac with nitro to remove non condensables.

  3. #3
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    What would eaven cause that? I have never seen a blower wheel fail in person.

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  4. #4
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    But we tested it and the static was low.

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  5. #5
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    Quote Originally Posted by R600a View Post
    But we tested it and the static was low.

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    Winner...

    High static loads down the wheel, causes stress at the joints...

    We have seen a few come apart...

    Remember the Trane plastic blower housings back when... not pretty at all when they came apart!
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  6. #6
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    I was joking about the fact that the static would be low in that condition

    Does the high static cause over speeding from reduced load?

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  7. #7
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    High static causes increased load...

    Ever study a water pump 'cavitation'... it is VERY destructive to the pump...
    GA-HVAC-Tech

    Your comfort, Your way, Everyday!

    GA's basic rules of home heating and AC upgrades:
    *Installation is more important than the brand of equipment
    *The duct system keeps the house comfortable; the equipment only heats and cools (and dehumidifies)
    *Cheap is not good, good is not cheap; however expensive is not a guarantee of quality!
    Choose your contractor wisely!

  8. #8
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    Maybe with an EC motor. But traditionally, on a conventional blower motor, the more static, the less load on the motor.


    Quote Originally Posted by ga-hvac-tech View Post
    High static causes increased load...

    Ever study a water pump 'cavitation'... it is VERY destructive to the pump...
    I do a triple evac with nitro to remove non condensables.

  9. Likes troutfiend liked this post.
  10. #9
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    Quote Originally Posted by ga-hvac-tech View Post
    High static causes increased load...

    Ever study a water pump 'cavitation'... it is VERY destructive to the pump...
    NPSH is what affects cavitation not necessarily "high static". I believe the issue with deadheaded pump is more to do with heat building in the impeller and seals because no water Is being moved.

    Cavitation isn't relevant to fans.

    If the fan was running a super high static it would unload the motor on a forward curved wheel. Low static would overload the motor. I have nothing to offer on whether that is good or bad for the wheel.

  11. #10
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    The only thing I can think of that could damage a squirrel cage is vibration from imbalance or rough handling. I would be interested to learn if there was some other cause though.

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  12. #11
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    I've seen the hubs get destroyed if they are windmilling backwards on start. The torque from getting it to go the correct direction is what takes them out. Generally on larger equipment.
    I do a triple evac with nitro to remove non condensables.

  13. #12
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    That is interesting. What causes them to windmill?
    Quote Originally Posted by BBeerme View Post
    I've seen the hubs get destroyed if they are windmilling backwards on start. The torque from getting it to go the correct direction is what takes them out. Generally on larger equipment.
    Sent from my SM-J260A using Tapatalk

  14. #13
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    Building pressure.
    I do a triple evac with nitro to remove non condensables.

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