Troubleshooting Gate Operators

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Warning: Troubleshooting gates should only be done by trained service technicians due to the dangers of injury, death, and property damage from electrocution, and the possibility of crushing, breaking, or severing of limbs from moving parts. All gates should be installed and serviced by trained professionals and meet all local, state, federal, and UL guidelines and safety regulations.

If the gate closes on vehicles or people, immediately open the gate using a manual override, block access to the gate, or leave the gate closed. Once the gate is secured in the position you wish, turn off power to the gate until repairs can be made. DO NOT allow operation of the gate when it's safety devices are not operating to specifications.

Vehicular gate operators are NOT intended for pedestrian traffic. A separate "man gate" should be used for pedestrian traffic in and out of a facility.

Most gate problems occur due to a lack of maintenance or improper maintenance. Gates should be regularly serviced by a trained service technician. A regular routine of service and maintenance should be planned for in the budget and scheduled throughout each year. Typical maintenance tasks that should be performed on gates include:

  • Oil and grease gates with the recommended lubricants. This includes the chain on gates that use one. Do not use WD-40 to lubricate the chain.
  • Clean parts using the proper solvents.
  • Inspect wheels, gears, chains, and other moving parts for wear or damage and replace immediately if necessary.
  • Adjust the chain tightness regularly. Do not have the chain adjusted too tight. You should have about 2" to 3" of chain "droop".
  • Clear weeds and rocks away from the chain and gate path.
  • Keep track free from debris and in good working order (unbroken and not lifting up or bending).
  • Check the limit screws and adjustment nut regularly. Your gate should not close into it's catch with a bang. It should come to a stop just before contacting any catch fork installed on the fence.
  • Test loops, beams, and sensor edges regularly and immediately replace or repair them if not working correctly.

Types of Malfunctions

Gate operator problems can be broken down into three different situations.

  • It won't open;
  • It won't close;
  • Or it's stuck partway and won't do anything.

In all three situations, the first thing to check is power.

  • Is the breaker tripped? If it is, reset it. If the breaker trips again immediately or soon after resetting it, the operator is pulling too much current. This could be a result of the gate binding or sticking, or an electrical fault in the operator. Do not reset the breaker again until this is fixed.
  • Most operators have a reset switch on the motor itself.[1] This is a thermal overload and will trip if the motor gets too hot. Reset it and see if the gate then functions[2]. If the motor overload is constantly tripping, this is an indication that the gate itself may be damaged or incorrectly balanced[3], or that the operator itself is underpowered for the application.
  • Some operators have a fuse on the control circuit board inside the operator. Check to see if the fuse is blown and replace if it is. Make sure to replace the fuse with one of the correct type and current rating. This should be marked on the board or a label inside the operator. Do not assume that the blown fuse you took out is the correct type. If the fuse blows again after replacement, this is an indication that the control circuit board or one it's accessories (loop detector, edge sensor, radio remote receiver, etc.) is damaged and will need to be replaced. Try disconnecting all accessories and replacing the fuse again. If it does not blow, reconnect the accessories one by one until it does to locate which accessory is causing the problem.

If the power seems OK and the overload is not tripped:

  • If the gate does not open, use a short length of wire to short the terminals for the gate open input. This may be labeled "Gate Vend" or the like. If it opens with this then the problem is somewhere back towards the access device. If it does not open then troubleshooting should be directed at the control circuitry for that particular brand of operator.
  • If the gate will not close, disconnect the wires for the gate open input and see if it will close. if it does not, check any safety devices installed on the gate. Loop detectors, beams or reversing edges. The gate control board may or may not have indicator LEDs showing the status of these safety inputs. Common failures for safety devices are:
    • Loop detectors
      • Bad or incorrectly installed[4] loop.
      • Loose or broken connection from the detector to the loop wires.
      • Bad loop detector, or no power to the detector.[5]
    • Safety Beams
      • Obstruction to the beam. (Dirt on lens, vegetation)
      • Misaligned beam.
      • Loss of power to the beam components, or bad beam.
    • Safety Edge
      • Malfunction or short circuit in edge.
      • Edge being contacted by part of gate / fence.


  1. Several different brands of gate operators use the same 1/2 HP motor in their products.
  2. This reset switch may be hard to operate with a fingertip. Sometimes it requires a tool to press in sufficiently. If the motor is still hot, this overload may not reset until the motor is allowed to cool off.
  3. A correctly balanced slide gate should be able to be pushed easily open and closed with one hand (with the chain disconnected). If you have to push the gate very hard to get it to move, it's not balanced correctly. A correctly balanced lift gate will, when it's clutch is released, settle into a position halfway between open and closed.
  4. Some examples of a bad installation of a loop can be incorrect placement (too close to metal objects or the gate itself) failure to twist the wires from the corner of the loop back into the gate operator, wrong kind of wire used, etc.
  5. Loop detectors for gates are set up to "Fail Safe" if the detector or loop goes bad, which will hold the gate open.