Most commercial operators drop into hold-to-run mode when they stop getting a good signal from their safety devices, usually the photo eyes or the safety edge. The door will still close, but only while someone holds the button and watches it. The fix is often realigning or cleaning the photo eyes, or repairing a failed edge or its wiring. Never bypass the devices to restore normal closing.
What hold-to-run means
Most commercial door operators have two ways of closing. In normal mode, one press of the button sends the door all the way down. In hold-to-run mode, also called constant pressure, the door only moves while someone keeps the button pressed, and stops as soon as they let go.
Operators switch to hold-to-run on their own when they cannot confirm that the closing path is clear. The idea is simple. If the operator cannot see, it needs a person to watch the door instead. So when a door at a warehouse, shop or strata parkade suddenly needs the button held, the operator is usually telling you that one of its safety devices has stopped reporting properly.
The safety devices involved
Photo eyes
Two sensors mounted low on either side of the opening send an invisible beam across it. If the beam is broken while the door is closing, the door reverses. If the operator cannot get a clean signal from the eyes at all, many units will only close in hold-to-run.
Common reasons the signal fails:
- One sensor has been bumped by a pallet, cart or bumper and no longer lines up with the other
- Lenses are covered in dust, road film or condensation
- A bracket has loosened and the sensor droops
- Wiring is pinched, chewed or corroded where it runs along the jamb
- Low autumn sun shining straight into a receiver at certain times of day
Safety edges
A safety edge is a sensing strip along the bottom of the door that reverses it on contact. If the edge is torn, waterlogged or its coiled cord is damaged, the operator may treat the edge as faulty and switch to hold-to-run. On some systems a monitored edge reports a fault even when nothing is touching it.
Why the wet season makes it worse
In Coquitlam, hillside areas such as Westwood Plateau and Burke Mountain get more rain, cooler nights and occasional snow. Condensation on lenses, water inside a damaged edge and corrosion at connections all become more common once the autumn rain starts. Doors on the towers around Coquitlam Centre, and on older commercial buildings near Maillardville and Austin Heights, see the same pattern when wiring and sensors have been in place for years.
What staff can safely check
These checks involve no tools and no work on the operator itself.
- Clear anything sitting in the opening or near the sensors.
- Wipe both photo eye lenses with a soft, dry cloth.
- Look at the indicator lights on the sensors, if they have them. Steady lights usually mean they see each other. Off or blinking lights usually mean they do not.
- Check whether either sensor has been knocked or is pointing at the floor.
- Look along the bottom edge of the door for tears, flattened sections or a loose cord.
If a sensor is only slightly out of line and it can be nudged back by hand without loosening anything, that can be enough to restore normal closing. If it needs brackets moved or wires touched, leave it for a technician.
What not to do
It can be tempting to get the door working normally by jumping out the safety circuit, taping the eyes together or unplugging the edge. Do not do this. Those devices are what stop a heavy door from coming down on a person or a vehicle, and a door running without them is a real hazard. Keep using hold-to-run, with someone watching the door the whole way down, until it is repaired.
If the door is noisy, crooked, has a loose cable, or you heard a bang, stop using it completely and keep people and vehicles out from under it. That points to a spring or cable problem, not the safety devices.
What a technician will look at
A technician will usually check the safety devices first, then the operator.
- Realign, clean or replace photo eyes and their brackets
- Test the safety edge and its cord, and replace a damaged edge
- Trace and repair wiring between the devices and the operator
- Check the operator's settings, travel limits and any fault codes
- Confirm the door is balanced, since a heavy door can upset some operators
Most of these repairs take a few hours. If the operator is old and parts are no longer available, the technician can explain your options for replacing it.
When to call a professional
If cleaning the lenses and a quick visual check do not bring back normal closing, it is time to call. A door that needs the button held is safe only while someone watches it, and that is hard to manage on a busy loading bay or a parkade that residents use all evening. Having it repaired gets the door back to normal while keeping the safety devices doing their job.