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Interconnected Locks


Sargent 7500 Series Interconnected Lock

An interconnected lock is actually two locks that are connected by an assembly that retracts both the deadbolt and the latch simultaneously when the inside handle is turned.   This is done to fulfill the life safety requirement under NFPA 101 that egress should be accomplished by one motion with no prior knowledge necessary, and at the same time provide the user with the security of a deadbolt.  The same function could be provided by an entry function mortise lock, but interconnected locks are cheaper, since they are usually cobbled together out of (usually) a grade 2 cylindrical lock and a tubular deadbolt.

The history of the interconnected lock is a twisted, strange story of different companies reinventing the wheel with different distances between the centerlines, connected or separate latch/bolt assemblies with correspondingly different strike preps, and radically different hole patterns on both interior and exterior door surfaces.  The end result has been many, many doors and frames prepped for locks that are now irreplaceable.

Today, preps are much more standardized.

These are some of the interconnected locks available today and the measurements of their preps:

  • Falcon H Series – 4 inches CTC, 1-3/4 inch hold above, 2-1/8 inch hole below
  • Schlage H Series – 4 inches CTC, 1-1/2 inch hole above, 2-1/8 inch hole below
  • Schlage S200 Series – 4 inches CTC, 1-1/2 inch hole above, 2-1/8 inch hole below
  • Schlage CS200 Series – 4 inches CTC, 2-1/8 inch holes above and below
  • Sargent 75 Series – 4 inches CTC, 2-1/8 inch holes above and below
  • Yale 4800LN series – 4 inches CTC, 2-1/8 inch holes above and below

Replacing any of the locks above with any of the others would not present an enormous problem.


Sargent 7500 Series Door Prep

New PS914RFK Retro-fit Kit from Von Duprin

According to IR tech support, the PS914RFK is a bracket and main board assembly designed to install into existing PS873 enclosures.  The idea is to ease PS873 replacement and it looks to me like it will accomplish that.

In addition to the PS873, you will need to replace all existing option boards that are present.

  • To replace 871-2, use 900-2RS
  • To replace 873-BB, use 900-BBK if you need batteries included.  If not, use 900-BB for the board only
  • To replace 873-FA, use 900-FA
  • To replace 873-4TD, 873-AO, or 873-SI, use 900-4RL
  • To replace 873-2Q, use 900-2Q

The following boards have been discontinued:

  • 873-AL
  • 873-AC
  • 873-DE

In several pieces of Ingersoll Rand literature I have seen the 900-BB board depicted as if it includes batteries.  It does not.  So if you want your battery kit to come with batteries, you need to get the 900-BBK.