How to adjust down force on Overhead Door Model 455 Operator?
My unit has two sets of adjusting screws one on the side for how far down the door is to go and how far up the door is to go. It has a set of adjusting screws on the back for the amount of force it will take to reverse the door if it finds an obstruction when coming down (like somebodies foot or a kitten). Set a 2X4 on the ground and close the door on it. If it reverses as soon as it hits the board you are OK. If it tries to keep going down then you need to lessen the force. It only takes very little bit of turn to adjust.
