Our GDO is a crafsman 1/2 hp. The door opens fine, however when it closes it stays closed all the way for about a three count and then opens back up. Any suggestions and help would be apprecited.
Forgot to mention...the only thing I see that may be a reason is there is alot of slack in the chain, it hangs down 3-4 inches. Any ideas on hoe to adjust this...thanks again.
It sounds like your door is hitting the floor and the safety is reversing it. On the side of the motor unit you will find a couple controls. One is the 'down limit'. Turn this control a turn or two in the opposite direction of the arrow printed on the cover. You may have to tweak it a bit to get it just right. Remember when you run the opener to adjust this you may cause it to shut off on the thermal overload. Just wait about 15 minutes and it will reset itself.
There are adjusting nuts on the trolley which is the thing the door is connected to. Don't over tighten the chain. It should sag a little. If it is mis-adjusted you will hear a clicking sound when it is running.