Electric latch retraction device for vertical rod door latches

An electric latch retraction device for driving a vertical rod door latch comprising:

• a pivoting retraction lever having an end adapted to drive the vertical rod door latch;
• a limit switch mounted to detect a position of the retraction lever at a pivoting limit of motion thereof and provide a limit signal indicative thereof;
• a linear sensor providing a vertical position signal corresponding to a vertical position of the pivoting retraction lever;
• a linear driver mounted to vertically drive the pivoting retraction lever;
• a control circuit connected to drive the linear driver in vertical motion and connected to receive the limit signal and the vertical position signal, the control circuit driving the pivoting retraction lever in vertical motion and detecting installation position errors of the electric latch retraction device relative to the vertical rod door latch from the limit signal and the vertical position signal by determining whether the electric latch retraction device has been installed in a position that prevents sufficient range of motion of the retraction lever when driven by the linear driver to properly operate the vertical rod door latch, such installation position error being identified by the control circuit driving the linear driver until the limit signal is received and determining from the vertical position signal that sufficient additional travel is available for the linear driver to drive the retraction lever and correctly operate the vertical rod door latch.