A.O. Smith GPS-75 Instruction Manual page 31

# led status
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proBleM
Self diagnostic check has detected
a problem with the gas valve driver
circuit, internal microprocessor, or
other internal circuits.
The gas control valve/thermostat
has sensed main burner flame out
of proper sequence.
Water temperature in the tank has
exceeded 195° F and has activated
the ECO (energy cut off) high
temperature limit.
Self diagnostic check has detected
that one or both of the temperature
adjust buttons are stuck.
Self diagnostic check has detected
the water temperature sensor
(located in the control valve's
immersion probe) is either open or
shorted.
Self diagnostic check has detected
a problem with black resistor wire
on the ignitor assembly plug;
resistor wire is open or shorted.
Self diagnostic check has
determined resistance of the black
resistor wire on ignitor assembly
plug is not within tolerance.
The gas control valve/thermostat
has detected the air pressure switch
circuit is opening repeatedly during
one heating cycle.
31
solutIon
1 Turn the power off for 10-20 seconds then on again to
clear these error codes.
2 If any of these error codes persist or cannot be cleared
- replace the gas control valve/thermostat.
1 Turn the power off for 10-20 seconds then on again to
clear these error codes.
2 Replace the gas control valve/thermostat if this error
code persists.
1 Turn the power off for 10-20 seconds then on again to
clear these error codes.
2 Replace the gas control valve/thermostat if the error
code persists.
1 Press and release both temperature adjust buttons
several times - cycle water heater power off and on.
2 Replace the gas control valve/thermostat if the error
code persists.
1 Turn the power off for 10-20 seconds then on again to
clear these error codes.
2 Replace the gas control valve/thermostat if the error
code persists.
1 Turn off power to the water heater. Ensure black
resistor wire is not cut, missing, and is installed
between pins 3 & 4 of ignitor assembly plug. Replace
ignitor assembly if damaged or defective.
2 Replace the gas control valve/thermostat if the error
code persists.
1 Turn off power to the water heater.
2 Replace the igniter assembly plug.
3 Replace the gas control valve/thermostat if the error
code persists.
1 Ensure air pressure switch hose is not kinked or
clogged, ensure the blower housing is clear of any
condensation.
2 Check vent temperature limit switch - if it is determined
that the vent temperature limit switch is opening its
contacts at normal operating temperatures during
heating cycle - replace the vent temperature limit
switch.
3 Ensure water heater is not over-firing. Call the technical
support for further assistance.