Thank you for question.
Cold winter time can be a challenge for garage door openers.
It is not uncommon for openers not to work when it gets really cold, but not at 20 degrees, maybe 20 below 0.
Do you have any Ice or Snow build up under the door that will need to be removed, because the door is freezing to the floor?
If I understand you correctly you are turning the force adjustments. And you have turned them all the way up, but the opener still will not open the door.
Is the opener motor unit trying to run and you hear a humming like it wants to run, versus not even attempting to run or turn on?
When it gets really cold the metal on the door and door parts like the grease in the rollers becomes very stiff and it takes extra power to lift the door.
Disconnect the door from the opener and see if it will run without the door attached.
If it does you have a door issue and will need to have the door serviced by an overhead door service company.
You could try lifting the door to waist height and then letting the door go to see if it is heavy and moves to the floor. A properly balanced door should not move from the waist high position up or down more that 4 inches. If it does it needs to be balanced by a door service.
If the opener will not even attempt to run it could be a component on the control board that is more temperature sensitive that it should be and may need to have the logic board changed.
Please respond through the link with what you have found and so I can give you a more precise fix for your opener.
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