Preload
101

What is PRELOAD?

Preload is pressure exerted on a door and in turn transferred to the keeper of the electric strike by the latch. This can disable common electric strikes causing the unlock mechanism to fail and not release properly. 

Why is it important?

Failure to release can prevent a door from opening, hindering safe passage or egress which could create a life-safety issue. Additionally, a door left unlocked by a faulty electric strike leaves a building vulnerable. 

What CAUSES Preload?

Causes could include: 

  • Stack pressure caused by HVAC systems
  • Misaligned hardware
  • Warped, damaged, misaligned or poor installation of doors and frames
  • Thick door seals or heavy weatherstripping

A strike that doesn't open or opens only intermittently could be showing signs of a preload problem. If preload pressure causes a strike or multiple strikes to malfunction, many access and security issues arise. 

Common SIGNS of Preload?

What to watch out for: 

  • Markings on strike plate whereby the latch is rubbing when door is closed
  • Door marks on frame where door is rubbing due to tight clearance
  • Door skin loosening due to excessive force and wear and tear on the door
  • Excessive paint chipping near frame strike or on door latch areas

SOLUTIONS for Preload

The Ultraline 7400 & 74R Series electric strikes address preload and more

The  7400, 74R1 and 74R2 Electric Strikes are designed to handle pressure and compensate for door and frame related preload and security problems allowing for consistent and proper operation of your access control system.

With a robust and compact design featuring adjustable stainless steel split-jaws and over 1,500 lbs of holding force, the 7400 & 74R Series electric strikes are unique because they are capable of releasing with up to 25 lbs. of door preload. 

Product Details

7400 Series

  • Designed for use with Adams Rite deadlatches and an array of cylindrical locksets with 1/2" to 5/8" latchbolt projection
  • Opens electrically under 25 lbs of preload
  • Dual voltage 12/24 VDC
  • Field selectable fail safe/fail secure
  • Faceplates available in a variety of size, shape, architectural finishes

More details >

74R1, 74R2 Series

  • 74R1 is designed for use with rim exit devices with ¾” Pullman latchbolts
  • 74R2 is designed for narrow stile rim exit devices with ½” Pullman latchbolts
  • Opens electrically under 25 lbs of preload
  • Dual voltage 12/24 VDC
  • Field selectable fail safe / fail secure
  • Faceplate is not separate

More details >

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