1. When the key cannot be fully inserted into the keyhole when opening the door, if it is in winter, first check if there is ice in the keyhole; if it is other seasons, check if there is any foreign matter in the keyhole.
2, I heard the metal friction sound of the switch door, you can try a little lubricant on the hinge of the security door, if it is invalid, you can find a professional maintenance worker.
3. When the security door is closed, the resistance is too large, and a little lubricant can be applied to the movable bolt.
4. When installing the security door, the cement should be carefully filled to make the door frame and the wall effectively and tightly combined, so that the door body and the door frame can be properly matched for long-term use without worrying about deformation.
5. If it is difficult to insert the lock cylinder when opening the door, you can apply a little graphite. Or insert the lock cylinder with a pencil lead.
6. In the severe cold area, the problem of "wintering" of the security door is also very important, because the indoor and outdoor temperature difference in the severe cold area is very large, and it is easy to make the lock core of the security door damp when it is hot and cold, and then freeze it. The situation occurs. Before the arrival of winter, it is necessary to drop two drops of antifreeze oil in the lock cylinder, and then wash it with gasoline or diesel after the winter. Vegetable oil is not available as a lubricant for the lock cylinder.