Chamberlain liftmaster LA412, tech advice needed

nancyk · Dec 21, 2019

I need some technical help w/my Chamberlain liftmaster gate opener LA 412. I spent way too many hours on this today and have finally given up. Following is what I have emailed to Chamberlain support.

"Our gate. solar powered, was not working correctly, it did not close all the way. I purchased a new post bracket, the previous one which had been bent. I should mention that it appears someone put something(glue?) into the lock on top of the piston arm so I am not able to manually release the swing arm. To let the gate move freely I have to pull the pins, in 2 places. One that connects to the gate and a second that connects to the pull-to-open bracket. We replaced the post bracket and two carriage bolts and tried to make sure all was level. The gate appeared to be opening and closing well from the Remote, then we tightened all the bolts/nuts, which must have put something out of whack. The gate was closing too far and setting off the beeper. After this happened more than a few times we tried to SET LIMITS. We followed all the directions in the manual but even after pressing LEARN LIMITS, the SET OPEN light was still blinking. I finally gave up. I should mention that since we cannot manually release the piston arm, I had to disconnect it from the gate to open it. Does the arm need to be attached to SET LIMITS? Since I cannot do that, what are my options? I closed up and left the gate, the SET LIMITS light still blinking. I pressed SBC, RESET, nothing could shut it off. And my Remote, which had been working until I attempted to SET LIMITS, is not talking to the gate."

The gate is level and plumb, and the Remote was functioning well w/the gate until I attempted to adjust the closing place(when the gate closed and hit the post, it viewed that as an obstruction and re-opened just a bit). I am missing something but do not know what.

Nancy

Chris616 · Dec 22, 2019

Hi Nancy,

Yes, the opener needs to be connected to the gate in order to set the limits. The control board isn't actually learning how far open/closed the gate is, but rather how far the opener piston is extended when you define the open/close limits. That all needs to be done with the opener release lever in the "engaged" position (which you've said is the only position that you can have it in because of a problem with the lock). After pushing the "Learn Limits" button, you open the gate using the button on the board and stop when you get to fully open. When you push the "Learn Limits" button again you're telling the opener that this much extension of the opener piston is what "full open" is. That is the only thing that it has knowledge of, not actually how far open the gate is. Ditto for the closed position.

Now, it may be that I'm completely misreading your post, because I can't understand another way that you would be setting the limits. If that is the case, I'll have another go at a solution if you have another go at a problem explanation.

Chris

nancyk · Dec 22, 2019

"the opener needs to be connected to the gate in order to set the limits" O.K. Good to know. I thought that possibly I could manually put the gate in the CLOSED position(the piston arm being disconnected from the gate) but now the poor piston does not know what to do as it is probably programmed to be OPEN and CLOSED at the same place, as the piston was not moving along with the gate.

"After pushing the "Learn Limits" button, you open the gate using the button on the board and stop when you get to fully open"
Which button is that? I went back out this morning and the SET LIMIT light is still blinking. I pressed the RESET button but that did not appear to change anything.
In the manual it says to press the Gate 1 button at certain times. Is that always necessary? Also, the gate is currently in the OPEN position as that is where the piston arm is and I cannot get it(the piston) to move in or out using the remote. So I cannot get the gate into the CLOSED position unless it is unconnected from the piston arm.
Thanks for your help, this is so frustrating.

Chris616 · Dec 22, 2019

References are to this doc, Nancy.
http://embed.widencdn.net/pdf/plus/cgi/vedbvaw8r6/0134491.pdf?u=btczgn

See the diagram on page 36 that shows where each button is located.

The "Gate 2" buttons are only required if you have a gate with two arms. You haven't mentioned that, so in your case you'll only use the "Gate 1" buttons.

Assuming that you've got a single arm gate, the steps are on page 29. In the following I've guessed that yours is a "left-hand side opener". Review the diagram in the middle of page 11 where it shows "Determine position of the pull-to-open bracket". If my guess was wrong and you've got a "right-hand" gate, then everywhere that I've written "left-hand button in the "Gate 1" grouping of two buttons" you'll need to use the right-hand button (and vice versa).

1. Start off by pressing the "Reset" button on the outside of the box. The gate should be closed at this point.
2. Press the "Learn Limits" button (#19 on the diagram). This tells the control panel that you're about to show it what the limits of the gate opening are. Again, you're really telling it what the limits on the opener piston travel are for the open and close position of the gate. The "Set Open Limit" LED (red light) to the left of the "Learn Limits" button should start to flash.
3. Use the right-hand button in the "Gate 1" grouping of two buttons to use the opener to open the gate. The manual doesn't say this, but it you overshoot and need to close the gate a bit just use the left-hand button. When you've got the gate where you want it to be when fully open, push the "Learn Limits" button again. That tells the control board that when the piston moves to this position that the gate is fully open. There should be a "beep" from the control board telling you that it's worked.
4. The manual doesn't say this, but I think that the "Set close Limit" LED to the right of the "Learn Limits" button will start to flash at this point and probably the "Set Open Limit" LED will stop flashing.
4. Use the left-hand button in the "Gate 1" grouping to use the opener to close the gate (again, if you overshoot use the other button to move in the other direction). When at the closed position, push the "Learn Limits" button again. That tells the control board that when the piston moves to this position that the gate is fully closed. There should be a "beep" from the control board telling you that it's worked. The "Set Open Limit" and "Set Close Limit" LEDs should both have stopped flashing now.

You might end up doing this a few times, because if you take more than 60 seconds between steps (like if you're reading the manual or a printout of this message), the programming will time out and you'll have to restart.

I don't have the same model of gate opener, but the principals are similar to mine (and also similar to how Chamberlain garage door openers are set up).

Chris

Chris616 · Dec 22, 2019

Hmm...give me a few minutes to think about some things that you wrote in your last message, Nancy:
"I pressed the RESET button but that did not appear to change anything"
"Also, the gate is currently in the OPEN position as that is where the piston arm is and I cannot get it(the piston) to move in or out using the remote. So I cannot get the gate into the CLOSED position unless it is unconnected from the piston arm."

Chris

Chris616 · Dec 22, 2019

I'm assuming that there are no physical problems with the opener, but the fact that the post bracket was bent might suggest otherwise. I can't diagnose that remotely, so I'll just concentrate on the controls part of the issue and we'll hope that is the only problem.

Just above the "Gate 1" grouping of two buttons is an LED labelled "Diagnostic". It might be flashing, and the pattern of the flashing can help us to figure out if there is a problem (see page 37 of the manual). It might not flash while the system is in programming mode, which it seems that it is right now.

"Also, the gate is currently in the OPEN position as that is where the piston arm is and I cannot get it (the piston) to move in or out using the remote. So I cannot get the gate into the CLOSED position unless it is unconnected from the piston arm.

OK. That is unfortunate that you can't unlock the opener. We'll need to modify the procedure. I think that it will still work. Back in step #2 in my earlier message you've just pressed the "Learn Limits" button and the "Set Open Limit" LED should be flashing. At this point (step #3) you can use the left-hand and right-hand buttons in the "Gate 1" grouping to move the gate to where the fully open gate position is. But if it is already in the perfect position you should just be able to push the "Learn Limits" button again to tell the control panel that this is the open position.

"I went back out this morning and the SET LIMIT light is still blinking. I pressed the RESET button but that did not appear to change anything"

I don't have a good answer for this. The programming mode should time out after 60 seconds, so I would have expected the "Set Open Limit" and "Set Close Limit" LEDs to not be flashing. In any case the Reset button should stop them flashing so that you can restart the programming process again by pushing "Learn Limits". At this point I would disconnect/reconnect the batteries to reboot the computer (see page 28).

(On an unrelated note I'll warn you to heed the warning note on that page. I've just finished cleaning up a mess from the 5 year old batteries that leaked in my gate system control box).

Chris

nancyk · Dec 22, 2019

the gate is currently in the OPEN position- I'll bet that is what you are thinking about. I finally managed to (lightly) force the key into the slot on the arm but it does not turn. My neighbor believes someone put something(he says glue) into the slot. We managed to carefully(with a very small flat screwdriver) pick out some very hard stuff from the slot, a small spring even came out, which may come from the lock??? I tried very hard to turn the key but nothing is budging and the key is almost bending it is so lightweight. I have printed out your instructions about Reset. I do have the manual and have been going by their suggestions. BTW, I do have a single gate, right-hand, pull-to-open.
All instructions call for setting the OPEN limit first, with the gate starting at CLOSED. Could I set the CLOSED limit first and do this backwards?

Chris616 · Dec 22, 2019

No. The controller on the board isn't flexible.
- Pressing "Learn Limits" the first time puts it into programming mode.
- Pressing "Learn Limits" the second time tells it where the gate open position is (actually the piston extension position).
- Pressing "Learn Limits" the third time tells it where the gate close position is (actually the piston extension position).

I'm fairly confident that doing what I wrote in my previous message will work. The controller doesn't really "care" what you're doing with the two "Gate 1" buttons. You could use those two buttons to open/close the gate as many times as you want while in the "Learn Limits" steps. The only thing that it is doing is making a note of the piston position when you stop moving the gate and press the "Learn Limits" button the second time (in the process above). That tells it "this is the open position" and it will, in the future, move the piston to that position when you ask it to open the gate.

Chris

nancyk · Dec 22, 2019

Thanks Chris. I pressed RESET but again, nothing happened. The SET OPEN light keeps blinking. The diagnostic light did blink when I pressed RESET. I cannot get the piston arm to move and I do not want to force it. I tried heating the key with a lighter to see if that would help the lock open. It did not, I tried it twice. I officially have given up, unless someone can come up with an idea for how to unlock the piston arm. There is a local man who says he has worked w/liftmaster gates(he asked me to call back Monday) so I am going to see if I can talk him into coming out for a remedial. First thing he asked me was Who installed the system?(it was not him, it was my husband), so the man may not want to come out. We will see.
I truly appreciate your time with attempting to fix my gate opener.

Nancy