I just installed a Chamberlain WD832KEV garage door opener. The modular rail that came with it is not straight. (Photo attached. Door slightly open.) I noticed that immediately after assembling it, but I chose to believe that something might magically correct the bend later. The belt makes contact with the rail just before the door finishes closing so there is a possible wear issue in addition to it being annoying to look at. Should I just claim warranty and ask for a new rail?
I'm pretty sure I did everything as detailed in the installation manual. I oriented each section exactly the same. Makes me wonder if each section has an identical bend to it, adding up to one big bend after assembly. Maybe turning every other section over could somewhat straighten out the assembly?
The bend in the rail is the main thing, but it's also pretty noisy when the motor first starts to close the door. There is a clank and bounce. (Master bedroom directly over garage. Clanking not welcome!) Once it's moving it's not so bad. (I'm planning to shoot a video of that issue.) It's perfectly quiet when opening the door. It's a belt-drive model, but it has an AC motor. Not sure if that accounts for the rough start.
The door is an old, wooden two-car sectional. It doesn't seem to be balanced perfectly, but not terribly bad. One of the two torsion springs was recently changed by a door company.