Electric garage door - problems opening and closing

[tan8856]

For a few months I have been having issues with my electric garage door. Its started doing 2 things
1) It goes down to close, touches the floor, then comes straight back up again so im unable to close it
2) It closes but it then wont open - when i look inside the 'error' light is on as is the light in the sensor at floor level. The only way i can get it open is by manually opening it by turning the handle a few times which raises the door a tiny bit, the error light then goes off and i can then electronically open it.
Im thinking this is probably all to do with the sensor? Ive tried hoovering out the area and wiping with a damp cloth but no luck. It seems that the door is going too far down when it closes, so that the pressure on the sensor from its own weight is making it think there is something under it so it is opening itself for safety reasons. Do you agree? Is there usually a way to minimally adjust how far it comes down to stop the sensor being activated? Or is it likely something else?
Apart from the above issues it works fine, it goes up and down ok once its 'released' and the error light has gone off.

 

[flameport]

Is there usually a way to minimally adjust how far it comes down to stop the sensor being activated?

Mechanical limit switches usually on the motor or somewhere near it. They are what stop the motor at the fully open/fully closed position.
One or both will require adjustment.

The other sensors are for safety purposes and are not related to how far the door opens/closes.

 

[stillp]

Are the tracks clean and properly lubricated? If it's the sort that uses motor current sensing instead of limit switches it might have too much friction.

 

[Tdw1982]

Do you have a transmitor unit on the bottom edge of the door - usually a grey or black strip of plastic, sometimes with a small LED)?
If so, unscrew the cover off this and replace the batteries first off.

 

[tan8856]

Do you have a transmitor unit on the bottom edge of the door - usually a grey or black strip of plastic, sometimes with a small LED)?
If so, unscrew the cover off this and replace the batteries first off.

Hi Tdw. Im going to attach a pic of the bottom of the garage door at the end where the sensor is. Is it a transmitter unit? We thought it was just a sensor. On the end of it is a circular bit of clear plastic that flashes orange when there is an issue with the door. It flashes when the door is stuck closed or closes and then bounces straight back open. Can i somehow unscrew it and there will be a battery in there? It doesnt look particularly unscrew-able. Thanks.

 

[Tdw1982]

This is more the sort of thing I would be looking for.
It would be on the inside of the door, and is on either the corner or the centre of the bottom edge. It does depend on the type of roller shutter, but they are quite common in garage doors.
It transmits the doors position as it passes certain sensors normal attached to the frame, wall or runners.

 

[tan8856]

This is more the sort of thing I would be looking for.
It would be on the inside of the door, and is on either the corner or the centre of the bottom edge. It does depend on the type of roller shutter, but they are quite common in garage doors.
It transmits the doors position as it passes certain sensors normal attached to the frame, wall or runners.

Found the transmitter but no battery inside, just a wire leading to the power source.
Any other ideas?

 

[bernardgreen]

That appears to be a junction box connecting the flexible ( spiral ) cable to the two cables that go into the frame. They are almost certainly cables to sensors built into the bottom of the door. These would be to detect an obstruction when the doors is closing and has not yet reached the fully closed position.

I suspect there is an adjustable limit switch in the motor / gear box that determines when the door should stop moving downwards just before it touches the ground ( with a separate limit switch to stop it in the fully open position ). If the downward limit switch setting has changed ( wear and tear ) then the door will touch the groumd before it stops. The sensors will see the ground as an obstruction and immediately cause the door to move upwards.