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Posted by Dennis on March 26, 2007, 6:12 pm
One other possibility is too much spring to overcome. Test by releasing the
door pull and see how much foce is present to manually close the door.
> The following is assumming your door is running on overhead tracks
> (sectional door) and not a 1 piece door with or w/o track. As I presume
> this
> is the 3/4hp chain drive, (53990) you will get some initial torque when
> the
> motor starts up due to chain slack.
>
> Check to see if the guides have any rack in them. This can cause some
> binding leading to your start-up torquing of the door mechanism. Rack
> being
> the diagonal measurments of the guide frame.
>
> |\ / |<<measure digonally from ends to a given point of the
> equal length along the guides
> | \ / <------- Diagonal rack
> | \ / |
> | \ / | This would be a view from the top or bottom of the
> tracks
> | \/ |
> | / \ |
> | / \ |
> | / \ |
> |/ \ | <given point> Can be 10',12', 14' etc. etc. Just a
> check to make sure the guide frame is "square" and not a parallelogram
> (http://mathworld.wolfram.com/Parallelogram.html) nor a trapezoid (
> http://mathworld.wolfram.com/Trapezoid.html
>
> You state;
>> The mounting is solid and the open position is proper (i.e it is open
>> just
> short of level and not at a backwards slant).
>
> I hope 'just short of level' is somewhere around +/- 3/16" in 8' from
> track
> to track. (IE: Both tracks are @ the same elevation) In reality, the
> tracks
> need not be dead level from the door frame opening to the end of the
> tracks
> by the motor, but it's better if they are. You can also check to see if
> the
> door is binding, when in the up position, by using the manual release.
> Pull
> the release and push the door to the down position, see if you are getting
> any initial binding in the full open position. If it's binding in the
> uppermost position, it should be fairly noticeable because the door will
> hang and then travel quite freely after you've moved it down some
> distance.
> You can also test this theory by lowering the upper limit in the full open
> position. Say you reset the upper limit to only open 3/4's of the way.
> Then
> activate the door and see if you are getting the same torquing as when the
> door is in a more raised position.
>
> HTH
> Dan
>
>> I installed a new 3/4 horsepower Craftsman garage door opener. Went
>> well, no problems. Close position set and open position sets well.
>> However, when in the open position, and I push the botton to close the
>> door, the initial motion is extremely bouncy and tourques the arm
>> upwards before continuing on it's path to close.
>>
>> The mounting is solid and the open position is proper (i.e it is open
>> just short of level and not at a backwards slant).
>>
>> Is my problem the angle of the arm from the wall to the motor unit?
>> Or...any other ideas?
>>
>> Thanks Steve-O
>>
>
>
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