How to Open a Maglock That Stays Locked
Two different faults, release failure and holding failure, and how to tell them apart
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To open a maglock that stays locked, use the exit button or the green break glass point on the escape side, which cuts power to the magnet. If the door still will not release, the magnet is still receiving power, often because of a faulty exit button, a stuck relay or a wiring fault. Never force the door or disconnect fire alarm links; the release on the escape route must always work, so call an engineer if it does not.
A magnetic lock, or maglock, secures a door using an electromagnet mounted on the frame that clamps onto an armature plate fixed to the door itself. It has no moving parts in the traditional sense, so faults tend to fall into two very different categories: the lock refusing to release when it should, or the lock failing to hold the door firmly once it is meant to be secured.
These two faults have almost opposite causes, so it matters which one you are actually seeing before doing anything else. A maglock that will not release is usually a power or control issue, since the magnet needs power removed to let go. A maglock that will not hold, by contrast, is far more often a mechanical or alignment problem between the magnet and the armature plate.
Because maglocks are wired into fire escape routes and release systems, any adjustment beyond the simple checks below should be left to an engineer. Getting the release path wrong on a fire door is a genuine safety issue, not just an inconvenience.
What You Will Usually Notice
Safe Checks You Can Do Yourself
Check whether this is a release fault or a holding fault
Watch carefully whether the door fails to open when it should, or opens too easily when it should be held shut. These point to opposite causes, so identifying which one you have saves time before an engineer arrives.
Look at the visible gap between magnet and plate
With the door closed, check by eye whether the electromagnet and the armature plate are meeting flush. A visible gap, even a small one, dramatically weakens holding force and is often caused by a door that has dropped slightly on its hinges.
Note whether the fault follows a pattern
A maglock that fails to hold only at certain times, or after the door has been slammed repeatedly, gives useful clues about whether vibration or heat is loosening something, which helps an engineer diagnose it faster.
Check nothing is obstructing the door itself
A door sweep, mat or draught excluder catching the bottom of the door can prevent it from closing fully square against the frame, which stops the magnet and plate meeting correctly even if the lock itself is working.
What Normally Causes It
Power continuing to reach the magnet when it should be cut
Maglocks release by having power removed rather than applied, so if a relay, controller output or fail-safe wiring fault keeps voltage present, the magnet will stay clamped shut even when a valid release signal is sent.
Misalignment between the magnet and the armature plate
Doors settle over time, hinges wear, and frames can shift slightly with the building. Even a small amount of misalignment reduces the contact area between magnet and plate, weakening the hold and sometimes allowing the door to be pushed open.
A worn or loose armature plate mounting
The plate on the door is usually fitted with a small amount of self-adjusting play to help it seat against the magnet. If the fixing screws work loose, this play increases too much and the plate can sit at a slight angle, reducing holding force.
Debris or paint build-up on the contact faces
Dust, paint or corrosion on either the magnet face or the armature plate stops the two surfaces meeting flush, and even a thin layer is enough to noticeably reduce the magnetic hold on a busy commercial door.
A failing power supply reducing available current
As with any electromagnetic device, a maglock needs its rated current to generate full holding force. A power supply that is degrading, overloaded, or shared with too many other devices can leave the magnet running under strength.
A fault in the release circuit, exit button or fire alarm interface
Maglocks are commonly wired to release on a fire alarm signal, break glass unit or exit button as well as normal access control. A fault anywhere in that chain can either stop a valid release from happening or, in rarer cases, cause the lock to behave unpredictably.
The door has physically dropped or the frame has shifted
Heavy use, humidity changes affecting timber frames, or hinges wearing over years of service can gradually change the exact position of the door relative to the frame, which is often the underlying reason a previously reliable maglock stops holding well.
When to Stop and Call an Engineer
Keeping it from coming back
Have door alignment and the magnet-to-plate contact checked periodically, particularly on heavily used doors, so a small mechanical drift is corrected before it turns into a holding failure or a release fault on a fire route.
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Frequently Asked Questions
How to Open a Maglock That Stays Locked: common questions
If the system needs replacing rather than repairing,
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