Door won't open or close. flashing yellow light on unit advice?

Check the resistance down button (There is one for down and another one for up). You may need to adjust the sensitivity. That way even if for some reason the have hard time coming down, less sensitivity may solve that issue.

https://www.youtube.com/watch?v=Izqj8I_BjHA

Look at the back of the motor unit and see if that little light is flashing a code. Post the code.

maybe a problem with the sensor 'door open/door close' check if its dirty or stuck if mechanical. press door to close and hold tight close while starting to identify.- or no sufficient water supply- or used water cannot drain out

If when closing the door it reverses to the open position and the main light flashes 10 times it is a door sensor problem. Make sure the small light on each sensor is on and not flickering ever so slightly. (check closely) Tweak them a little even though they may seem to be okay. Check for 5vdc between terminals 2 and 3 on the rear of the motor unit. If there is no voltage or if it is greater than 6vdc the logic board is bad.

If the door reverses when it hits the floor it is traveling too far. Locate the 'down limit' control on the side of the motor unit and turn this in the opposite direction of the arrow printed on the cover. Some tweaking will most likely be necessary. You can always recognize a sensor problem because the main light will flash 10 times. If the main light isn't flashing it isn't a sensor problem.

Anytime the main light flashes 10 times and the door reverses to the open position it is a door sensor problem or the wiring to them. Nothing else causes this symptom.

If the main light flashes 10 times when the door reverses it is a sensor problem. Make sure the door isn't hitting the floor and then reversing. This problem will not cause the light to flash 10 times and can be corrected by adjusting the 'down limit' which is on the side of the motor unit.

# of flashes

1

2

3

4

5

6

Rapid Flashing





Problem

The Protector System wire open or totally misaligned

The Protector System wire shorted or black/white wire reversal

Door Control or Multi-Function control Panel wire shorted

IR sensor slightly misaligned (dim or flashing sensor LED)

Motor overheated/Possible RPM sensor failure -- unplug to reset

Motor circuit failure -- replace RX/LX board

Liftmaster transmitter with the correct format code being received
(opener not necessarily programmed to respond)

It is normal for that LED by the learn button to flash randomly. It can also flash a code to help with diagnosis. The codes are 1 to 6 flashes followed by a pause and then repeats. A rapid flash is a sign it is receiving a radio signal but not necessarily the correct one to operate the door. If when your door doesn't close properly the main light flashes 10 times and the door reverses to the open position it is a door sensor problem. The sensor must be pointed at one another and sometimes can be off just a hair and will cause intermittent problems. A slight tweaking of the sensors will cure this problem. The 'down force' adjustment can be set too low and cause the door not to close sometimes. This can be increased to overcome this problem. This problem will not cause the main light to flash. The other possibility is the RPM sensor. This is the printed circuit board that senses when the door runs into something. I have never seen one intermittent but that doesn't mean it's not possible. I hope this helps you.