The open and close limit on any garage door opener is the point that you set so the opener will know where to stop on the way down and where to stop so that the garage door is all the way open. There are several different ways that liftmaster chamberlain products use to set the open and close limits one way is manually with a screwdriver and the other two ways are set by pushing buttons on the control panel to move the garage door up and down and the brand new line of chamberlain liftmaster openers that have the myq technology are even a little different to set.
Opener model numbers that are adjusted manually:
1000, 1000e, 1000sd, 1000sdc-r, 1000sdr, 1000sdc, 2000sdc-r, 2000, 2000e, 2000sd, 2100, 1200, 120ad,1210e fs2, 1215e fs2, 1215em fs2, 1220e fs2, 1225e fs2, 1240r, 1245, 1245lmc-r, 1245r 1246r, 1250, 1255, 1255r, 1256, 1260, 1265, 1265-267, 1270, 1280, 182638, 182638d, 182638dm, 182649, 182649d, 182665, 182665d, 182671, 182671d, 2220, 2220-267, 2200 rgd, 2245, 2245c, 2255-2, 2255c, 2265, 2265c, 2267, 2280, 2280-267, 2280-976, 2280c, 248730, 248735, 248739, 248754, 2500,2500b, 2500bc, 2500c, 2500d, 2500dc, 2565, 2565c, 2575, 257856, 257858, 2580, 2580c, 2585, 2585c, 2595, 2595c, 2595lm, 3112, 3122, 3240, 349544, 4200c-2, 459950, 4620, 4620-2, 4640, 4640-2,4640-2k, 47995d, 547445, 6200, 6200-2, 6200-2k, 7220, 7320,7420, 7902, 7902k, 7902kd, 8200, 8200c, 9200, 9200-2k, 9500-3k, 985, 9902, 9902c, 9950, 9950d, 995xd, 9960, cg40, cg40cd, cg40cs, cg40d, cg40dm, cg40s, cg42cd, cg42cs, hd150dm, hd175dm,hd200d, hd400d, hd400dm, hd600, hd600ds, hd700d, hd700ds, hd800d, hd900cd, hd900d, hd900ds, lw2000, lw3000, lw500ev, m100, m150, m200, m50, m75, m700, ml750, mt60p, pd100, pd100c, pd200, pd200c, pd210, pd210c, pd210cd, pd210cs, pd210s, pd212, pd212cd, pd2125, pd300d, pd300dm, pd420, pd420-2, pd420d, pd422d, pd428d, pd432d, pd432dm, pd458d, pd460-2, pd460-2k, pd462d,pd505d,pd600, pd600c, pd610d, pd610s, pd612, pd612s, pd752, pd752cd, pd752cds, pd752ds, pd752kld, pd752klds, pd758d, pd758ds, pd758kd, pd758kds, pd248735s, pd7520d, pd432d, pd7920kd, wd822c, wd822k, wd822kc, wd822kd, wd822kld, wd822kls, wd822ks, wd822ks, wd822kd, wd822kev, wd912k, wd922ks, wd922k, wd922kc, wd922kcd, wd952kcd, wd952ld, wd962kd, wd962kev, wd962kld, wd962kpev, wd962mlev, wd248739, 8500, 8550, 8587, 8557, 8360, 8355.
Run garage door one complete cycle
Before you set the open and close limits you should first run your garage door through one complete cycle push either the remote button or the wall control button and let the door open and then close if the door does not open or close completely or the door does not stay closed or it hits the ground and goes back up then you most likely need to adjust the open and close limits if you are installing an opener yourself that you bought at a retail hardware store and you need to set the open and close limits for the first time then you most likely will not have to run the door through a cycle because they almost never open and close and then stop where they are supposed to do when they are new out of the box. First you will need to have a ladder and then you will need a flat head screwdriver and if you have a handheld remote it makes it a lot easier also if you do not have a remote then it would be easier to have someone help you so they can push the wall control button so you do not have to go up and down the ladder several times to complete this procedure. Any time that you make an adjustment you should run the garage door through a full cycle that means once up and then once down. These open air units come with a safety feature that will shut off the unit if the motor gets too hot from constantly running during the open/close limit settings. If the opener unit does shut down on you and stops working do not be alarmed just wait about 15 or 20 minutes and let it cool off a bit and then it will start working again. When you are making these adjustments at any time if the garage door stops or goes back up on the downward travel then you might have an unbalanced or binding or sticking door.
Open and close limit adjustment screws
The first thing you will need to do is locate the open and close limit adjustment screws they are either on the side of the opener unit or behind one of the light covers you will have to pull down the light cover if you cannot visibly see the adjustment screws they should be easy to find they are two plastic white screws usually with a picture of a garage door with a down arrow on one side for the down limit adjustment and on the other side would be a picture of a garage door with an up arrow to represent the up limit adjustment screw there will also be two circular arrows in the middle showing you which way to turn the screw for increasing the down limit or increasing the up limit. If your garage door does not open all the way then you will need to turn the right adjustment screw clockwise until it opens up just enough to where you can see the very top of your garage door opening that should be your limit that means that any tall vehicles will hit the top of the door opening before it hits the garage door. This procedure is the same for the down limit. When you are setting the down limit you want to make sure not to put too much limit turns on the screw because the door will go all the way down and then come back up unintentionally. The rule of thumb for the adjustment screws equals one full turn is 2 inches or 5 centimeters of travel distance. This is something you should keep in mind when you are turning the adjustment screws because if you have way too much travel you could sometimes do damage to your garage door or the opener unit. You also will want to have enough pressure when the door is in the down position to keep it snug to the opening so that it does not blow around when in high wind areas.