For locksmiths who are involved with commercial locksmithing, access control and system integration, Von Duprin products should be a familiar and preferred name. Von Duprin has become the standard for exit devices and more recently electrically actuated hardware. Recently we heard from a...
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Retrofits and Upgrades
Von Duprin bars lend themselves particularly well to retrofits and upgrades. On two recent occasions, we were required to upgrade existing Von Duprin exit devices, and we were able to modify the equipment without replacing it or compromising its listings.
In one situation, we installed a REX kit in an existing Von Duprin bar when the access control system required the installation of a card reader and electromagnetic lock. The exit device was equipped with classroom function outside trim. By installing the electromagnetic lock, the end-user achieved the flexibility of having both a positive latching and an always-locked outside lever if it became necessary so shut down entry on a door completely while not impeding egress. The REX kit upgrade requires disassembly of the exit device and the installation of a power transfer (in this case it is a signal transfer). For this project where only two conductors were being wired, an armored door loop was selected.
The other recent installation called for the upgrading of an existing Von Duprin surface-mounted vertical rod exit device with "Latch Retraction."
There are basically two ways a door with a Von Duprin exit device may be electrically actuated (controlled). First, use electrically actuated outside trim. When a signal is applied to the trim, the lever becomes "active" and turning the lever retracts the locking mechanism (latch or rods). A small amount of current is required.
Some applications will not permit the use of electrically actuated Trim. One example would be when the subject doors are also being opened by door operators. In that situation, the locks must be retracted before the door operators kick in.
Our project involved a pair of doors at a school which were equipped with Von Duprin exit devices with surface-mounted vertical rods. Theses doors were usually 'dogged down' during normal business hours, and they planned to continue this practice, even though a card reader was being installed. Electric Latch Retraction retracts the latch (or rods) when power is applied. The latch retraction feature has a 100 percent duty cycle, which means that the module is designed to remain energized for extended periods of time.
Installing the latch retraction module involves a few steps which may require both installation skill as well as a licensed electrician, depending on your particular job.
1- Remove the existing exit device assembly and replace the mechanical 'backplane' with the solenoid-operated unit.
2- Install a heavy-duty power transfer. (Refer to the Recent Locksmith Ledger Article on Power Transfers for a review of some of the options available) One additional option is available: the Von Duprin Electric Power Transfer. This unit is mortised into the hinge edge of the door and the jamb to provide a totally concealed (aesthetic and vandal-resistant) installation. It is supplied in two different versions, EPT-2 (2 #18 gauge conductors) and EPT-10 (10 #22 gauge conductors). Because of the infinite possibilities of installation conditions, you may be required to do what Von Duprin Tech Support refers to as some "field development." This means routing and perhaps fabrication of some brackets.
3- Install a Von Duprin Power Supply and connect it to line voltage (may require an electrician); to the power transfer (e.g. the exit device) and connect your card reader controller's dry contact output to the input of the Von Duprin Power Supply. The Von Duprin power supply may be purchased with a line cord which then means you need to be sure a line voltage receptacle is convenient located to the power supply.
4- Properly adjust the latch or vertical rods once everything has been reassembled and connected. Proper latch engagement with the rim strike and proper adjustment of the vertical rods with both the top trigger and bottom keeper are required for the exit device to not damage the floor over which it swings, to ensure that both the top and bottom rods properly engage, that the door will properly relock when the door recluses and that the exit device allows egress without requiring excessive pressure to be placed on the exit device to unlock it.