Hi Richard,
A rapidly blinking LED over one or more of the keys of the keypad indicates one or more key switch lines are stuck or shorted on either the control board or the keypad.
To determine which of the part is faulty, do the test recommended in the "Checking Keypad Operation" section in the tech sheet.
Post the results and the color of the control panel and I'll help you with the right part number. You can buy any of the needed parts from $66 to $95 which is less than the labor charge you have to pay for a warranty service.
Gene.