Question about Chamberlain Powerdrive PD422D 1/2 HP Security Plus Screw Drive Garage Door Opener

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Rail bows when door is closed

I have a Chamberlain Whisper Drive modelHD600. I've check and checked and have no idea why the main rail would bow when the door closes all the way, its subtle but still it bows. If I adjust the down travel so it doesn't bow, the door does close all the way. Any ideas?

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What you describe is common with those operators.

Posted on Jan 02, 2009

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Are you sure about that, Door Tech? I had this same problem with the opener I installed and called Chamberlain tech support today. The person told me that the rail should not bow, and that it was doing it because the wall header bracket wasn't mounted 2" above the highest point of travel of the door (it was higher than that). I told her I didn't see how this would correct the bowing. If anything, I told her, it would make it worse because the rail would be lower and the straight door arm would push it up more. I also told her that it would make the rail more level, which she also told me would cause bowing. But, I did it to humor her. The result was I had to shorten the length of the straight arm because it bowed quite bad, as I suspected. This didn't eliminate all the bowing, however, and now the door won't reverse when it closes on a 2 x 4. And if I increase the down travel, it just makes the bowing worse.

Posted on Aug 31, 2010

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Would a "T" rail prevent this? I know Chamberlain used to offer the drives with them. The bowing is driving me nuts!!! I hope there is no wear on the motor because of it.

Posted on Mar 28, 2010

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