How to Tell If Your Gate Operator Is Pre-2016, UL16, or UL18
Two automatic gate operators can sit side by side, look nearly identical, and behave completely differently the moment you connect them. One runs with nothing but a remote wired to it. The other refuses to move until photo eyes are installed and recognized. The difference is the version of UL 325 the operator was built under, and there are three generations in service today: operators built before 2016, operators built under the 2016 revision, and operators built under the 2018 revision.
Knowing which one you own answers a lot of practical questions. It tells you what safety devices your gate needs, why it behaves the way it does, and what will happen if you replace the control board. This guide walks through how to identify your generation, starting with the fastest method and ending with what to do once you know.
Why It Matters Which UL 325 Version You Own
The three generations differ in one important way: how they treat external safety devices like photo eyes and safety edges. Older operators treat them as optional. Newer ones will not run without them. If you are adding an accessory, replacing a board, or troubleshooting a gate that suddenly stopped working, the generation is usually the missing piece of the puzzle. Buy a sensor that does not match your operator's generation and it may not work at all.
Check the Data Label to Identify Your UL 325 Version
Every listed gate operator carries a data label, usually a metal or printed plate on the housing, that lists the model number and the date of manufacture. The date is the single most reliable way to identify your generation.
Use the manufacture date to place your operator into one of three generations:
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Pre-2016: manufactured before January 12, 2016.
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2016 revision (UL16): manufactured between January 12, 2016 and August 1, 2018.
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2018 revision (UL18): manufactured on or after August 1, 2018.
Those two dates are the dividing lines, and the manufacture date on the label tells you which side of them your operator falls on.
Write down the model number while you are there. If you later need safety devices, the model number is what determines which monitored photo eyes and edges are on the approved list for your operator.
No Manufacture Label? Identify Your UL Version by Behavior.
Labels fade, peel off, or get painted over. If you cannot read yours, the operator's own behavior will tell you which generation it is. This test takes a couple of minutes and tells you what you need to know.
Start by watching how the gate runs normally with everything connected. Then, with the gate stopped, disconnect or block one of the photo eyes and try to run the gate again. How the operator responds is the giveaway.
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Pre-2016: the gate runs with nothing connected to its safety terminals at all, and keeps running whether photo eyes are present or not. Nothing on the control board is checking for external devices.
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2016 revision (UL16): the gate runs under normal conditions but stops automatic operation the moment you unplug or fault a photo eye. It is monitoring its devices and refusing to run blind, which is exactly what the 2016 revision required.
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2018 revision (UL18): the gate will not run at all until the required monitored devices are installed and recognized by the control board. The photo eye is not an accessory on this unit. It is a prerequisite for any movement.
What Each UL Generation Actually Means
Once you have identified your generation, here is the short version of what each one represents, so the behavior makes sense.
A pre-2016 operator was built when external safety devices were recommended but not enforced. Manuals of the era said photo eyes and edges should be installed, but the operator ran the same whether they were wired in or not. A great many of these gates went in with no external safety devices at all, relying only on the operator's built-in obstruction sensing.
A 2016 operator was built after the standard began requiring monitored devices. A monitored photo eye or edge communicates with the operator continuously so the control board can confirm it is present and working. If the operator loses that signal, it stops automatic operation rather than running without protection. This is why these units shut down when you unplug a sensor.
A 2018 operator was built under the current seventh edition of UL 325, in effect since August 1, 2018. These operators will not run until the minimum required entrapment devices are installed, connected, and verified. The standard also sets how many devices each gate type needs, which is why a modern slide gate typically ships with photo eyes covering the open and close paths plus safety edges on the leading edge and pinch points.
Why Did My Gate Stop Working After Replacing the Control Board?
The most common reason owners need to identify their generation is a board replacement. Current replacement boards are built to the current standard. That means dropping a new board into an older operator can suddenly require monitored photo eyes and edges the original installation never had. The gate that ran fine for years on a remote alone may now refuse to move until the safety devices are in place.
This is not a defect and it is not the board malfunctioning. It is the new board doing exactly what the current standard requires. The catch is that it surprises owners who were expecting a simple swap. If you are replacing a board on an older operator, plan for the safety devices as part of the job, and confirm the ones you buy are on that operator's approved list before you order.
Should You Upgrade an Older Operator?
There is no regulation forcing you to retrofit a working pre-2016 gate. If it runs and you are happy with it, you are not breaking any rule by leaving it as is. That said, the entrapment protection rules exist because moving gates genuinely injure people, and a pre-2016 gate running with no external safety devices has the least protection of any generation. Adding monitored photo eyes and safety edges to an older operator is one of the most worthwhile safety upgrades you can make to a gate system, and it brings an aging gate much closer to how a modern one protects the people and vehicles around it.
Still Not Sure Which Generation You Have?
If you cannot find the date on the label, or the behavior test left you unsure, we can help you sort it out. Have your operator's model number handy if you can find it, and our team can confirm which generation you are working with and which safety devices pair with it.
Talk to an expert at (800) 555-6017, Monday through Friday, 8AM to 4PM PST. We will help you figure out what you have before you order anything.