If it’s a 1600 series Generation 1 or 2 (metal enclosure and no LED display inside)), disconnect the power, set the unit ID switches to 0-0, and reapply power.  The status light will blink very fast.  Wait a few seconds, remove power, change the Unit ID switches back to where they were and reapply power.  You’ve reset the board.  

If it’s a 1600 series Generation 3 (metal enclosure with LED display inside), disconnect the power, press the up and down buttons simultaneously and reapply power. The display will show ‘0000.’  Wait a few seconds, release the up and down buttons, the controller will be reset and return to normal operation in about two seconds.

If it’s a CTB-16PC series Generation 1 or 2 (plastic enclosure and has a jumper block to the right of the data cable connectors), disconnect the power, remove the jumper next to the data connectors (usually in the second position (or J2)) and reapply power.  The status light will blink very fast.  Wait a few seconds, remove power, replace the jumper on the J2 position and reapply power.  You’ve reset the board.  Go into the Hardware Utility and make sure the board is assigned to the correct physical location where it was before the reset.  

If it’s a CTB-16PC series Generation 3 (plastic enclosure and has a jumper block to the left of the data cable connectors), disconnect the power.  On JP3, counting from the left, move the jumper on pins 4 and 5 over one notch to pins 5 and 6.  Reapply power.  The status light will blink very fast.  Wait a few seconds, remove power, move the jumper pack to pins 4 and 5.  Reapply power.  You’ve reset the board.  Go into the Hardware Utility and make sure the board is assigned to the correct physical location where it was before the reset. 

If it’s a CTB-32 controller board (typically with a green status light), disconnect the power from the controller.  On reset header JP3 (just to the lower left of the data cable connectors), counting from the left, remove the jumper between pins 4 and 5.  Power up the controller and  the Status LED should flash rapidly.  Disconnect the power from the controller and put the jumper back on between Pins 4 and 5 of the reset header JP3 (MAKE SURE OF ITS LOCATION).  Power up the controller.