I fitted an RW1 Gliderol motor to each of my garage doors and they worked fine for about 10 months. Sometimes when i close them now they are auto reversing as if they have hit an obstruction which is how they are supposed to work if an obstruction is actually present. I've tried turning the force switch to the maximum and this has made no difference. The doors are about 8 years old so i don't think they are that worn, can anyone help as this is driving me nuts.