A.O. Smith T-H2-DV Service Manual page 63

B. Error code history
The T-H2-DV and T-H2-OS has an "Error-call button" on
the computer board that provides two main functions.
The button is located next to the dipswitches (please look
at the picture to the right).
B-1. Displaying error code history
1. Briefly press the "Error-call button" (do not hold down
the button).
2. If the T-H2-DV or T-H2-OS has had prior error codes, the
3-digit 7-seg LED will display the most recent error code
first. Pressing the button again will display the 2
recent error code and so on (Computer saves a maximum
of 12 error codes). If the T-H2-DV or T-H2-OS has never
had any error codes, the 3-digit 7-seg LED will blink a bar
"- - -" as shown the picture to the right.
B-2. Clearing error code history memory
1. Press and hold the "Error-call button" for at least
5 seconds.
2. The 3-digit 7-seg LED will display "CLr" in
succession to signify that the computer board
memory has been erased of all error codes.
T-H2-DV/T-H2-OS Service Manual
"Error-call" button 3-digit 7-seg LED
nd
most
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CONFIDENTIAL
Ver. 1.01