Garage door opens by itself

From Chamberlain's website:

There are a few different things that can cause this type of problem.

1. Look at the LED light next to the SMART/LEARN button on the motor unit. If you are facing the garage door, the SMART/LEARN button is located on the rear end or right hand side panel of the motor unit. You may need to remove a light lens cover in order to see it. This button is either purple, red/orange, green, yellow, grey, or white in color. If the light is flashing rapidly this means you have a stuck button on one of your remote controls. Take the batteries out of each remote control. When you remove the batteries from the bad remote, the light will stop flashing. This remote needs to be replaced.
2. If one of your neighbor's remote controls is inadvertently programmed into your receiver, your door will open when their remote is activated. If this happens you will need to clear out your receiver and reprogram your remote controls:
   
   1. Press and hold the LEARN button for six seconds, or until you see the small LED light near the button turn itself off.
   2. If the above steps have been followed and the symptoms continue, there may be an electronic short in either the wall control button or the receiver logic board. In this case, remove the wall control wires from terminals one and two (or red and white) on the motor unit. Should the symptoms persist after the wires are removed, replace the receiver logic board. If the symptoms stop with the wall control wires removed from the motor unit, replace the wall control button, and the wires leading to the wall control button.

When my door did this,it needed the down force increased.i quess i adjusted it too soft during the hot summer because it was not until the cooler fall weather {oct} when it started operating on its own.so,i would suggest{ before calling a door company} to check the up and down forces and the up and down travel limits.also test the safety reversal system.with the door fully open, place a 1-1/2 board {2x4 laid flat}on the floor, centered under the garage door.operate the door in the down direction.the door must reverse on striking the board. dean c. {louisville,ky}

Some older remotes use 9 bit encoders like the HT6026 that only generate 512 different codes. They transmit in the range of 433MHz and it is a open license radio band congested with cordless phones, hundreds of remotes in the area that can cause one of the 512 codes to be triggered. Electronic failure due to manufacturing, electrical surges, thunderstorms can also cause erratic behavior in receiver units. EMF from machines can possible generate enough RF waves with random fluctuations that can trigger remote events. Newer remotes are better by using rolling code features but even they are not fail-proof since the receiver can still go faulty. No electronic device is fail-proof and one should always take great care before relying personal safety or security on remote control devices.

Try checking the closed limit switch setting and the force adjustments on the opener.

I had this problem several years ago.  I read about a possible cause on the Internet and after thinking about my own experience, I think mine was caused by gas-powered blowers emitting noise that confused the simple analog door opener I had at the time.  
I bought a new Genie Intellicode upgrade kit & retrofitted that to my existing opener mechanism.  I have never had the problem since.  I think blower theory sounds a little sketchy but I have no other explanation.  In any case, the Intellicode remote upgrade solved my problem.

Adjusting the downforce also fixed this for me. My user's manual had pretty detailed instructions on how to adjust this. Mine was hitting the 2x4 on the ground and not going back up. Once I adjusted it so it went back up after hitting it, the door stopped randomly opening on its own.

For the people who have great heavy overhead garage doors be aware to do not repair on the motor /hand operating unit by yourself
Actually hear garage doors overhead doors such as garage doors s not under the fixya column for do it yourself repair because of a General Duty Clause can be applicable


Suggest brands like experienced by a specific model Crawford this units can have much problems that repeats every year again and again i have experienced that on the place where i am working and its every time again its an expensive job , but i have searched the defect but stop this activity because of safety clausules i have reading and know of very dangerous situations and accidents if so there are plenty of other brands that do have a better product with a special safety compliant thats equivalent fitting on the same overhead-door we will chose that but, stay away from self-recovery in the electric unit by doing yourself by this doors also not more to do then only do not more what the manual prescribes, if others are unwittingly a victim may because of the safety you cannot serve this kind of units by yourself (if there are others who may operate this door to, If the control seal ( paper label or red or black paint sealant) if thats broken which is in the motor unit and or hand control to present and there arises a personal accident through a door with whatever happens what and who intervenes and the door turns on and doesn't stop, the insurance pays a dime damage at a follow-up investigation as there is found to be improper working inside the unit.
only to say beware of the special way of safety

a real happend thing translated : Rb, part dispute: employer liable for any accident involving unsafe roller door in rented premises

Employee gets rolling door in which security cable failed on his head and walks injuries. The Subdistrict Court held that there had been an unsafe situation because no security was present at the roll-up door. This is employer liability under art. 7: 658 DCC a given, unless the employer can demonstrate that it has fulfilled its duty of care. Defense that the employer as a tenant Attn the building and the roller door had no security requirement, and that it was entitled to assume that the building was safe rejected. Even if a building is rented, the security obligation of the employer extends over the building. Cost partial dispute: € 5,692.50.

The wall controller can stick if pushed on the side or corner. Then any slight vibration such as a truck going by will activate the opener. On my Sears wall unit I pried off the plastic push button and put a spring (from the hardware store) inside to help push the button back out after use.

My garage had a similar problem a few years ago. It turned out the sensor was getting tripped by something. We couldn't figure out what it was, so we ended up calling a garage door company to come out and take a look at it. http://www.aceoverheaddoors.ca