Chamberlain LiftMaster Excessive Force Control Error. Perform the following tests: First, close the door and then disconnect the door from the trolley and operate the door manually. The door NEEDS to roll smoothly and not catch on anything and it NEEDS to be balanced and stay at any point you stop it. If the door wants to go down by itself the springs are weak and at fault; have a qualified service technician fix/ adjust them…they can be very dangerous to work with since they are under extreme tension.
Second, operate the opener without the door attached and see if it operates correctly. The trolley will fully go up and down if working properly. Performing these tests will help narrow down whether the door/ tracks or the motor unit is giving you the problem. Please let me know what you find from these tests and we can proceed from there.
