A.O. Smith 12 40GPC T 100 Water Heater User Manual


 
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Please check guidelines below. For your safety, water heater service should be performed only by a qualied service person.
Read the
GENERAL SAFETY INFORMATION
supplied by the water heater manufacturer.
1.
“POWER” Flashing
Communication Error
The system has detected a
communication error between the
upper and lower controls.
1. Check the 5-conductor data cable that
runs between the upper and lower
controls. Check that the wiring is not
broken, and the connectors on both ends
are properly seated in the mating
connectors.
2. Replace the upper control, if the error code
does not clear - cycle power to the water
heater “O” and “On” to reset.
3. Replace the lower control if the problem persists.
2.
“HEATING” and “SHORT” Flashing
The self-diagnostic tests have
found a problem with an internal
circuit.
1. Turn the power o for 10 to 20 seconds
then on again to clear the error code.
2. If the error code persists or cannot be
cleared, replace the lower control.
3.
“HEATING” and “OPEN” Flashing
Ignition/ame failure.
The water heater has reached the
maximum number of retries and is
currently locked out for one hour.
Cycle the power to the water
heater o and on to reset.
1. Gas supply is turned o – pressure too
low. Ensure supply and manifold gas
pressures are within requirements in the
installation manual. Manifold gas
pressure is non-adjustable, if pressure is
o by more than 0.3” W.C. (75 Pa)
replace the lower control.
2. Low supply voltage – should be 115 –
125 VAC.
3. Ensure ame sensor is making good
conta
ct with the burner ame, ensure
ame is steady.
4. Ensure the ame sensor is clean – use
pad
to clean the ame sensor.
5. Ensure the hot surface ignitor is
positioned to provide consistent ignition.
6. Check for any cracks in the ignitor
assembly ceramic insulators – replace
ignitor assembly if damaged.
7. Check resistance of the ignitor at room
temperature (77°F – 25°C) at the plug
end. Replace ignitor if the resistance is
not within 1.72 to 2.4 ohms at room
temperature.
4.
“HEATING”, “OPEN”, and “SHORT” Flashing
Weak ame sensor current.
1. Ensure ame sensor is making good
contact with the burner ame, ensure
ame is steady.
2. Ensure the ame sensor is clean – use
ultra ne steel wool or Scotch-Brite pad
to clean the ame sensor.
5.
“ECO” and “OPEN” Flashing
Water temperature in the tank has
exceeded 185°F (85°C) and has
activated the ECO.
1. Turn the power o for 10 – 20 seconds
then on again to clear this error code.
2. Replace the lower control if the error
code persists.
ultra ne steel wool or Scotch-Brite
TM
TM
CONTROL DISPLAY STATUS
PROBLEM
SOLUTION
ELECTRONIC CONTROL DISPLAY
ELECTRONIC CONTROL DISPLAY TROUBLESHOOTING