We’ve been having problems with our garage door for a while now, where when we tried to close it, the door would come down all the way to the ground then suddenly pull right back up as if someone gave it the open command. This would go on and on and trying to close a garage door a dozen times in a row is understandably frustrating. If you’re in this situation, here’s a list of things we tried that finally (I hope) got it to close for good.
Adjust Open and Close Force
When I called technical support, they suggested increasing the closing force of the garage. This might might vary from model to model, but our model (Chamberlain Liftmaster Professional 3/4 HP) had a screw on one side that, when rotated, increased the close force accordingly. I also decreased the open force a bit. This seemed to work for a couple of days but the door started acting up again after a short while.
Cover up the sensors
I noticed that the problem happened most often when it was sunny and a quick google search showed that other people had this problem, too. So first you need to understand how the sensor works. There is an invisible light, most likely infrared that is emitted by one sensor component and received by the other. When something obstructs this light travel, the sensor thinks that something is blocking the front entrance so don’t close the door. The issue here is that when sunlight hits the receiving sensor it might confuse it into thinking the door is obstructed or not. After all, sunlight is composed of many different wavelengths of light including visible light, UV and infrared.
The solution I tried was to cover up the sensors with a cardboard toilet paper roll. This still allows the light beam to travel straight between the sensors, but it protects them from any light hitting the sensor from the side. Again I got mixed results.
Switch sensor places
I had to call up a local garage door repair company for this one, but basically they just switched the locations of the sensors from one side to the other. Worked well the first day, but then stopped working again later on.
Adjust close and open distance
After exhausting all the previous options, I did the unthinkable. I read the instruction manual! Sure enough, there was a troubleshooting section with that exact problem and they explained that I could adjust the closing distance of the door. That is, how far down it should come when I command it. This turned out to be another pair of adjustable screws on the side opposite from the open and close force screws. I dialed back the close distance a bit and it looked like it worked again. We’ll have to see how long this one lasts.