LiftMaster Door Only Closes on Hold?

A commercial door on a LiftMaster Logic 5.0 operator opens with one push but only closes while someone holds the button down. Before assuming the operator is broken, check the safety devices: this is exactly how the operator is designed to behave when it can’t confirm the doorway is safe to close.

Why does my LiftMaster commercial door only close when I hold the button?

Because the operator has lost its monitored safety device, or never had one. LiftMaster calls these LMEP devices (LiftMaster Monitored Entrapment Protection): the monitored photo eyes, light curtains or sensing edges that watch the doorway while the door closes. The Logic 5.0 installation manual is direct about it: “If a LiftMaster Monitored Entrapment Protection Device is not installed, constant pressure to close will be required from the control station.”

Constant pressure to close means exactly what your staff are experiencing. The door only travels down while someone holds CLOSE, and stops the moment they let go. The idea is that a person with a finger on the button is watching the door.

Why is there a 5-second delay before it moves?

That’s the second version of the same behaviour. If the operator has learned an LMEP device and that device is blocked, misaligned or disconnected, the manual says you can still close the door with what it calls Restricted Close: hold the CLOSE button, and “the operator will begin closing after 5 seconds and will continue to close to the Close Limit or when the close button is released.” The pause is deliberate. It isn’t the motor struggling.

The manual’s troubleshooting chart describes it the same way: the door will open, but will only close after a five-second delay with constant pressure on the close button, and the first cause it lists is that the LMEP is obstructed or activated.

How to tell which one you have

Two places on the operator tell you most of the story.

• The LMEP light on the logic board. According to the manual, if the LMEP is misaligned, activated or disconnected, the LMEP LED on the board blinks on and off.
• The MAS light on the 3-button station. Logic 5.0 operators use the Maintenance Alert light to flash error codes. Seven blinks means the LMEP device has been faulted or removed for more than two minutes, and the operator is in “normal operation (5 second constant pressure override required to close).” It clears once the device is cleared or reconnected.

On a loading dock or warehouse door, typical causes are simple: a photo eye knocked out of line by a forklift or pallet, a lens covered in grime, a damaged cable to the sensor, or an edge that’s been crushed. Sometimes the device was disconnected during other work and never reconnected.

Things worth checking before you call

1. Clear anything sitting in the doorway or in front of the photo eyes, including stacked product, hoses and snow or ice at the floor.
2. Wipe both photo-eye lenses.
3. Look at the sensors and the wiring for obvious damage: a bracket bent out of line, a cut cable, a crushed edge on the bottom of the door.

Anything past that (opening the operator, testing wiring, realigning or replacing devices) is technician work, and the operator should be locked out before anyone goes inside it. If you clear the doorway and the door still won’t close normally, the device or its wiring needs attention. Our page on photo eye and safety edge repair covers what that involves.

“But the setting says B2. Isn’t that the safety rating?”

No. On a Logic 5.0 board, B2 is a wiring type, one of the selector-dial settings (alongside C2, D1, E2, T, TS and FSTS) that decide how the control buttons behave. B2 is momentary contact to open, close and stop. Separately, the UL 325 safety standard uses “Type B2” to describe a kind of safety device: a contact sensor, such as a reversing edge. Same letters, different meanings. Whether the operator closes on a single push depends on the wiring type and on having a working monitored device; the label on the dial doesn’t tell you whether the door is protected.

The same MAS light and DIAG setting are also how you read the operator’s built-in cycle counter; see reading the Logic 5.0 cycle counter. For the full picture on the safety devices themselves, including what monitoring means, see our commercial door safety devices guide.

Don’t wire around it

It’s tempting, on a busy door, to look for a way to make it close on one push without the sensor. Don’t. The constant-pressure fallback is there so the door doesn’t close on a person or a vehicle that nobody is watching. The fix is a working monitored device, properly aligned, on the operator it was made for. LiftMaster’s manual notes its LMEP devices are for use with LiftMaster commercial door operators only.

Need it fixed?

CCGDS is an authorized LiftMaster dealer and services Logic 5.0 operators across Metro Vancouver, with 24/7 emergency call-outs for doors that are stuck open or won’t secure the building. See LiftMaster commercial operator repair or commercial door operators, or call (604) 206-5727.

Source: LiftMaster Logic 5.0 commercial door operator installation manual (Entrapment Protection, Determine and Set Wiring Type, Troubleshooting and error code chart).