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Compatibility Issues

What’s wrong with this picture?

When specifying door hardware I understand that it can be like being an kid in a candy store.  But like that kid, you may not be able to always get everything you want.   Sometimes “this” might not go with “that.” There are some examples that should be obvious, such as fire rated exit devices with cylinder dogging, since fire rated exit devices must positively latch each time they close without exception and any kind of dogging could prevent that.  But other combinations of options are less obviously incompatible.

One elusive combination of exit device options that pops up sometimes is delayed egress with electric latch retraction.  In most electric exit devices this is almost a contradiction in terms because they use the same mechanism for delayed egress as they do for electric latch retraction, except it works the opposite way.  For example, the Von Duprin Chexit uses the same kind of motor that the Von Duprin EL devices use, except that the Chexit motor pushes out on the latch mechanism while the EL motor pulls in.  What would be necessary I guess would be to build a little transmission so one could shift gears from push to pull to switch from delayed egress to electric latch retraction and back again.

But since no one has yet invented this miniature transmission neither the Sargent Electroguard nor the Von Duprin Chexit currently offer both delayed egress and electric latch retraction in the same device.  The only device I have encountered so far that does offer these two options together in the same device is Detex.  There could be others.  Check with individual factories to be sure.

Two options that are offered together in many, but not all exit devices, with varying degrees of availability, are cylinder dogging and electric latch retraction.   For example, Sargent offers cylinder dogging with electric latch retraction, but only when factory installed.   Von Duprin offers “Special Dogging” (SD prefix) with electric latch retraction.  In this case the effect of cylinder dogging is accomplished by a cylinder operated latch holdback feature in the center case of the device.  (Not quite the same as traditional cylinder dogging.)  Precision can offer cylinder dogging and electric latch retraction in the same device without complication because their electric latch retraction and cylinder dogging mechanisms happen in different sections of the rail altogether.  Corbin and Yale offer devices with cylinder dogging and electric latch retraction in the same device.   Yes, the electric latch retraction and cylinder dogging combo is all over the charts when it comes to availability.

 





As in all facets of life, when in doubt, contact your friendly door hardware genius.

 

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