Electric strike buzzes but the door won't open
Applies to: Electric strikes on office access-control doors
What this error means
The buzz means power is arriving — the mechanism is mechanically bound. The classic culprit is 'preload': pressure on the door (HVAC stack pressure is the leading cause, plus warped doors, weatherstripping, sagging hinges) pushes the latch against the strike's keeper so hard the keeper can't pivot even when energized. The diagnostic is beautifully simple: have someone pull/push the door to relieve pressure while badging in — if it releases, it's preload. Other documented causes: wrong voltage or AC/DC mismatch (note AC strikes buzz by design; DC strikes are silent, so a NEW buzz on a DC strike means wrong power), and only after eliminating those, a failing solenoid.
Symptoms
- Buzz on badge/button but door stays locked
- Worse on windy days or when the HVAC runs (pressure)
- Works when someone pushes the door while badging
Try this first (safe DIY steps)
- Run the preload test: relieve door pressure during release — if it opens, you've found it
- Address the pressure source: door closer adjustment, weatherstripping, hinge tightening
- Check the spec plate: strike voltage should match the power supply (12/24V, AC vs DC)
Safety: power off before any physical intervention. Never bypass covers or interlocks — fuser areas run hot enough to burn.
When to call a technician
Persistent preload despite door fixes = install a preload-rated strike (HES, Adams Rite and others make them, rated ~25 lb). Solenoid replacement or rewiring is integrator/locksmith work — a like-for-like strike swap runs a few hundred dollars, far below a full access-control opening.