Im working on a garage door opener where the door opens properly but stops and reverses while closing but If you hold the button down it will fully close.I have looked at the sensors and can't say that i fully understand their sequence of operation.one sensor is sends and the other receives i guess?Anyway the green L.E.D on one sensor turns off if you step in the beam but the other other sensor L.E.D stays on.The motor controller flashes a code to indicate miss aligned sensors.The sensors have to be aligned because the L.E.Ds are on.Can they be bypassed?
The sensors are simply switches...they are either open or closed. There are also limit switches that "tell the contactor that the door is either fully open or fully closed. The door reversing like that could be caused if the limit switch at the top (near the motor) was shorting out. There could also be a fault in the internal interlocks in the reversing motor starter. Finally, if there are any "remote" transmitters, one of them could be acting up.
If the door we speak of is a residential single phase door, odds favor the circuit board- which controls all of this- is bad. If the door is a three-phase commercial door, then you will be more able to sort out the specific component that is bad.
The easiest thing is to firs remove batteries from any wireless remotes, and see if the problem still exists. If it does, you will have to sit down, draw out a line diagram, and sort it out one thing at a time.
A final caution: garage door hardware- even for the flimsiest, smallest doors, has more than enough energy stored in the springs to hurt, even kill, you. Don't be afraid to contract this one out to a pro. (I do that often).
The sensors are simply switches...they are either open or closed.
Well, they COULD be but because there are people who would do away with them if they were, most operators now use some type of signal coding where the transmitter and receiver have to be connected and at least pointing at each other for the operator to work. Disconnect them or short the wiring and the operator won't work.
Yep...simple problem...the sensors are not aligned properly. The opener thinks there is an obstruction. The door shuts when you hold the button, because you are "telling" the opener by conciously holding the button down to close the door. This is handy in case one of the sensors breaks or fails and you wish to close the door and are too lazy to close it manually.
hbiss, you are right these sensors cannot be by-passed because of DYIers.Apparently the controller has to see something like a 5V signal from the receiver sensor to start, shorting leads wont work. I still don't get it? i thought the sender was on all the time and receiver sensor l.e.d was the only one to turn off when you step in the beam or if it's out of alignment. If both sensor l.e.ds are on proving the beam is clear the controller should be accepting the signal voltage and operating or that was the logic i had adopted? (1) What is the is the signal the receiver produces and the controller is supposed to "see" in order for it to operate? (2) is there a device like a resistor or something i can use to produce this signal voltage? Basically all safeties appear ready so its either absence of proper signal voltage or controller malfunction.I just don't have a clue from that point on.thanks
If you know the sensors are aligned (take them off their brackets and hold them facing each other). If you still get an error that they are not aligned then it sounds to me like you have something defective. At this point unless you want to start changing parts (and can get them)I would refer this to an overhead door service company who should be able to see what the problem is and take care of it.