Why is a coordinator required when you have a Von Duprin 98/9975 with astragal and 98/9927 on the other leaf?

Typically the astragal would be applied to the Pull Side of the 9975 mortise leaf.  You want to make sure the 9927 leaf comes closed first so the 9975 leaf with the overlapping astragal closes second.  If the 9975 with the astragal closed first your 9927 leaf would be unable to close and latch.  The coordinator ensures that the 9927 leaf closes first.

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