A more well built version that has mechanical sensors is the 3265 the older brother to this opener and has the same look but black and separate force and travel dials

I wouldn’t be overly concerned with door #3 applying more pressure than the other 2 units, that’s what the safety sensors are for. On these electronic units I have found they don’t always work as intended. I’ve had units that the force setting were non functional right out of the box (had to replace the logic board). You can retrain the force settings by pressing the yellow learn button twice to enter the force setting mode (the up arrow should be flashing) press the up arrow to fully open the door, after the door completes an open cycle, the down arrow should be flashing. press the down arrow to close the door after the door completes its close cycle, setting the force is complete. If you want to reprogram the limits, the owners manual walks through this process. They are easy to set but can be finicky if you haven’t done it before.

The door you call number 1 sounds like my chamberlain 4200

I would suggest to increase the close travel by 1 quarter of a full turn to get the garage door to reverse, the force doesn't have anything to do with it in this case.

Why won’t that garage door opener reverse?

Do you have safety cables though spring? Please let me do

The problem with the opener not reversing is because it’s not closing as much as it should. Want me to make a video of what I mean?

Don't know if you still read comments on here. Just a tip, you might need to increase the down travel on the opener for number 3

why did you opt for extension springs instead of a torsion system

Nice love those garages

I like you doing this test and not staging it to work on all of them. You might need to increase the down travel. I'm not too sure how to do it for this one because it's electronic. I like the screws better. I guess it doesn't really matter if you don't have kids there

travel limits..bend the rail if you have to ..or sell your house, otherwise don't worry about it, tech since '93

you need to get the liftmaster 8550w

Did you know that 12voltvids made the video about his same product for his garage door opener where he has to replace with the new gear and made a rant video about the price what charge him to order parts in Canada? And I don't know why the door No.3 didn't do that to open the door back automatically, probably because like you said, it might be the sensitivity sensor who thinks it's clear and not in the way, but the door No.1 and 2, it works fine like it should.

Well as for #3 at least items you don't want crushed by the door would be more than 4 inches high You have a very nice garage!

who would put extension springs on a garage door that has the headroom for a torsion spring

And the door that you call number 3 is just like my chamberlain 4200 it does NOT reverse with the 2X4 but it does with more chain goes up like it to

ive never seen a t rail bend before

On door #3 how it is not reversing. Mine is doing the same thing.

I have a Chamberlain c450

Door number three is not traveling far enough

Like I said, in the old days, before the sensors at the bottom of the door, you used to put something like a basketball, far more than the 2 inches the wood provided. If that worked, it was good. Too bad it has to wait till the spring, being Millennial and stick... ;-p

At least they have emergency cords.