englander 25pdvc exhaust fan noise rattle

dave64 Posted By dave64, Dec 28, 2012 at 8:57 AM

  1. dave64

    dave64
    Member

    Feb 11, 2011
    45
    2
    Loc:
    N H
    the fan is making a rattle sound like the fan blades are hitting something and if i just tap the back of motor it stops for hours or even a day or so.
    everything is clean fan is tight to motor shaft and no marks on fan blades like its hitting anything.
    is motor going ? if so where can i get a cheap after market one

    thanks
     
  2. Harvey Schneider

    Harvey Schneider
    Minister of Fire

    Oct 9, 2012
    1,321
    321
    Loc:
    Southbury, CT
    I had the same symptom with the pdvc that I rebuilt. The culprit was the bearing carriers on the motor. The bearings on mine are mounted to the end plates of the motor, and the end plates are each held in place by dimples in the motor sleeve. All I needed to do is use a nail-set and hammer to tighten the dimples on the end plates. There is still some vibration, but the rattle is gone.
     
  3. dave64

    dave64
    Member

    Feb 11, 2011
    45
    2
    Loc:
    N H
    what are end plates and where are they
     
  4. Harvey Schneider

    Harvey Schneider
    Minister of Fire

    Oct 9, 2012
    1,321
    321
    Loc:
    Southbury, CT
    The motor is a cylinder with an external metal sleeve and two metal disks at the ends of the cylinder. The bearings are at the centers of those disks, Those disks are the end plates. The photo below shows the location of the dimples. There are several spaced around the circumference.
    10-1111b.png
     
  5. dave64

    dave64
    Member

    Feb 11, 2011
    45
    2
    Loc:
    N H
    ok great i will try that

    thank you
     
  6. TheDarkSide

    TheDarkSide
    Member

    Nov 12, 2008
    13
    0
    Loc:
    Southern NH
    Did this fix it for you? I have a similar problem with the rattle and the slightest pressure against the motor housing makes it stop, so I'm thinking it needs to be tightened. Funny thing is the sound on mine goes away after it's had a chance to run for a while.
     
  7. imacman

    imacman
    Guest

    Did you also try putting some oil in the bearings?
     
  8. Harvey Schneider

    Harvey Schneider
    Minister of Fire

    Oct 9, 2012
    1,321
    321
    Loc:
    Southbury, CT
    Motor rattle is caused by something moving colliding with something stationary. Sometimes it is caused by a rotor far enough off center that the vibration results in surrounding objects collide. More often the rotor gets far enough off center to collide with the stator. If you were to disassemble the motor and look at the rotor you would see scuff marks on it's circumference. In both cases it is more than oil can cure. Either the bearings (bushings) are worn beyond service or their carrier plate is loose.
    Fix or replace (or just wait until you can't stand the noise anymore) before the motor stops entirely. Without the convection blower running the stove will overheat.
     

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