By william machin you need proper tension on a garage door to operate the door by hand or with an automatic opener.
Proper chain tension on garage door opener.
Using a screwdriver remove the cover on the garage door opener and then replace the spent battery with a new one.
On the master link you will see two or three nuts.
There are only a few ways that the chain can be tightened.
Hold the garage door in this position by attaching a c clamp to the track at a point below the lowest door roller wheel.
Both adjustment types should be done with the door closed and disconnected from the opener using the emergency release.
Just because the door is open does not mean that the spring tension is fully released.
If the tension is too loose the springs that help lift the door are ineffective.
Usually a pair of nuts are associated with the locking mechanism while one is concerned with the adjustment of the chain.
If it does not open you need to replace the backup battery.
Unplug the garage door opener then try to open the door with the wall button.
Use the wrench to loosen the lock nuts and turn the adjustment nut to set the slack in the chain.
A properly adjusted chain will be above the base of the rail at its midpoint at inch for t rail or inch for square rail.
Replace the batteries in the door remotes.
Chain adjusts by shortening the chain itself.