|Photo: Frank Sandrin|
A problem came along after the assembly was complete and I tested the garage door opener. The trolly was parked where the door would normally remain closed. When I pushed the button, the door began to open but it didn't stop and hit the stop bolt causing a lot of stress on the chain. Eventually I got it to reverse back down but it didn't stop when it hit the ground causing the rail to flex and almost buckle.
|The culprit was the limit switch assembly|
Here are my steps to realign this module (this applies to most Craftsman garage door opener models):
- Unplug the garage opener.
- Ensure that chain isn't torqued against the bolt as this could be very dangerous to work on.
- Release the garage door from the trolley using the emergency release cord.
- Note where the trolley arm is parked. Is it in the down position, up position or somewhere in the middle?
- In Figure A, at the bottom of the gear & sprocket assembly shaft, there is a small white plastic piece called the Limit switch drive. It is attached with a plastic retainer clip, either pull this out with a set of needle nose pliers. Slide the drive off.
- You can optionally unclip the limit switch assembly (Figure B) and adjust it or adjust it in place. I did the latter. If your trolley is the completely down position, turn the drive gear (1) so that the centre limit contact (2) is closer to the drive gear or (the green line in Fig. B). Turn it to the middle position (yellow line in Fig. B) if the trolley is in the middle of the rail and if it is at the top, put it near the travel adjusting screw heads (red line in Fig B).
- The key is that when the garage door opens or closes, the centre limit contact moves up and down the centre white plastic drive gear screw.
- Assuming that trolley is in the middle of the rail, place the up and down contacts (3 & 4 in Fig B) so that they are about an inch away from the centre contact (sitting on the green and red lines in Fig B).
- If the trolley is all the way at the bottom, the down contact (3) should be touching the centre contact (2) over the green line and the upper contact (4) should be at the red line.
- Lastly if the trolley is in the all the way up position, have the upper contact (4) touching the centre contact (2) over the red line and the down contact a few inches away near the green line.
So that's it in a nut shell. Keep making small adjustments to both the travel and force adjusters in accordance with the manual or the instructions that came with any parts you ordered. Good luck and be careful!
Before working on garage doors note :
* the spring/s is/are under extreme tension and can seriously injury or kill you if you try to remove/adjust it
* the door can weigh over 400lbs
* the opener runs on 110v power
"According to the US Consumer Product Safety Commission, 20,000 people each year have been treated in hospital emergency rooms for injuries related to garage doors. The most common injury is fingers getting caught or crushed. Injuries relating to the failure of extension or torsion springs send approximately 1,000 people to hospital emergency rooms every year in the U.S.
Therefore, if you’re not completely sure of what you are doing, leave it to a professional