This is a very simple job to do yourself in fact all you need to do is follow this simple 6 step guide.
Tighten garage door belt.
In most cases all you have to do is adjust the opener belt of the belt drive tightening it to ensure smooth running.
The only thing you need to do with a belt driven opener is to adjust the belt occasionally.
All you need to get started is a step ladder a 7 16 inch wrench and a flat head screwdriver.
The specific procedure should be in the manual for your unit.
The belt needs to be connected with the tensioner loosened so that the tensioner can be used to take up any excess slack.
Brand new chamberlain garage door opener with excessive slack in belt drive.
The manual does not indicate how to solve this problem.
Loosen the adjuster three turns counterclockwise if the door raised without.
1 close the garage door.