A.O. Smith 12 50GPC T 100 Water Heater User Manual


 
23
Please Note:
The control continually monitors
internal circuits and external sensors.
Error codes noted above, and those for
self-diagnostic faults can be found on
pages 20 through 22.
APPLY POWER TO
APPLIANCE
YES
REQUEST
FOR HEAT
PRESENT?
NO
IS
PRESSURE SWITCH
PROVEN OPEN WITHIN
5
SECONDS?
NO
COMBUSTION
FAN ON
YES
IS
PRESSURE SWITCH
PROVEN CLOSED
WITHIN
11
SECONDS?
NO
WAIT FOR PRESSURE
SWITCH TO OPEN
DISPLAY ERROR
NUMBER
7
WAIT FOR PRESSURE
SWITCH TO CLOSE
DISPLAY ERROR
NUMBER
6
PREPURGE
IS
IGNITOR
OKAY?
TURN OFF
COMBUSTION FAN,
DISPLAY ERROR CODE
NUMBER
8
NO
IGNITOR ON FOR
WARM-UP TIME
YES
GAS VALVE OPENS
MAIN
BURNER LIGHTS
AND IS SENSED
DURING TRIAL
FOR
IGNITION
IGNITOR TURNS OFF
YES
NO
IS
FLAME SENSE
LOST?
IS
REQUEST FOR HEAT
SATISFIED?
GAS VALVE OFF
COMBUSTION FAN
OFF AFTER POST-
PURGE DELAY
GAS VALVE CLOSES
LESS
THAN
3
TRIES
FOR IGNITION?
GAS VALVE CLOSES
LOST
LESS THAN
4
TIMES?
YES
YES
TURN OFF
COMBUSTION FAN
AFTER POST-PURGE
DISPLAY ERROR
3
ONE HOUR
AUTOMATIC RESTART
TIME DELAY
NO
NO
NO
YES
YES
NO
IS
PRESSURE SWITCH
PROVEN OPEN WITHIN
5
SECONDS?
WAIT FOR PRESSURE
SWITCH TO OPEN
DISPLAY ERROR
NUMBER
7
INTERPURGE
COMBUSTION
FAN OFF
YES
NO
YES
COMBUSTION FAN
OFF
COMBUSTION FAN
ON
3 MINUTE
AUTOMATIC RESET
TIME DELAY
IS
PRESSURE SWITCH
PROVEN CLOSED
WITHIN
5
SECONDS?
WAIT FOR PRESSURE
SWITCH TO CLOSE
DISPLAY ERROR
NUMBER
6
NO
YES
IS
PRESSURE SWITCH
PROVEN CLOSED
WITHIN
5
SECONDS?
WAIT FOR PRESSURE
SWITCH TO CLOSE
DISPLAY ERROR
NUMBER
6
YES
NO
TROUBLESHOOTING FLOWCHART