Troubleshooting Guidelines - A.O. Smith 120 Series Instruction Manual

TROUBLESHOOTING GUIDELINES

Please check guidelines below. For your safety, water heater service should be performed only by a qualified service technician.
# LED STATUS
1
VAC A B C
2
VAC A B C
3
VAC A B C
4
VAC A B C
5
VAC A B C
6
VAC A B C
TROUBLE SHOOTING
Read the GENERAL SAFETY INFORMATION section first.
INTELLI-VENT TROUBLESHOOTING CHART - USER CONTROL
PROBLEM
Inadequate or no earth ground.
High resistance to earth ground or
reversed polarity in the 120 VAC
power supply.
Pressure switch circuit remaining
closed for more than 5 seconds
after heating cycle begins.
Blower may not start in this
condition.
Pressure switch circuit remains
open longer than 5 seconds after
the blower is energized.
Blower may run continuously in
this condition.
Open igniter circuit.
Ignition/flame failure.
The gas control valve/thermostat
has reached the maximum number
of retries (3) for ignition and is
currently locked out for one hour.
Cycle the power to the water
heater off and on to reset.
1 Ensure the wall outlet (power supply) is properly
grounded.
2 Ensure all ground connections/wires on the water heater
are securely connected.
1 Ensure that the water heater is securely connected to
earth ground.
2 Ensure that the wall outlet/power supply is properly wired.
Also, ensure that internal 120 VAC wiring connections
and the wiring harness have no reversed wires. 120 VAC
"hot" wire must connect to the on/off switch.
1 Ensure air pressure switch circuit wiring is correct and
the air pressure switch is not jumpered.
2 Replace the air pressure switch.
1 Ensure the air pressure switch sensing tube is properly
connected at both ends and is not kinked or damaged.
2 Ensure the correct size of vent and intake air pipe (direct
vent products) was used per the installation instructions
in the manual that came with the water heater.
3 Ensure maximum number of elbows or maximum
equivalent feet of vent or intake air pipe have not been
exceeded per the installation instructions in the manual
that came with the water heater.
4 Ensure there are no obstructions in the vent or intake air pipe.
1 Check wiring to the hot surface igniter assembly -
replace igniter assembly if wiring is damaged or worn.
2 Check resistance of the igniter at igniter assembly plug -
should be between 11 and 18 ohms at room temperature
(77° F at plug end) - replace igniter if open or shorted.
3 Check igniter assembly plug and the socket on the gas
control valve/thermostat for good connection. Replace
igniter assembly if the plug is worn or damaged.
4 Replace the gas control valve/thermostat if the igniter
assembly socket on the bottom of the control is worn or
damaged.
1 Ensure flame sensor is making good contact with the
burner flame and ensure flame is steady. Also ensure
supply and manifold gas pressures are within the
requirements in the installation manual.
2 Gas supply is turned off - pressure is too low. For low
gas pressure, consult with your gas utility.
3 Ensure the flame sensor is clean - use fine steel wool to
clean the flame sensor.
4 Check igniter assembly plug and the socket on the bottom
of the gas control valve/thermostat for good connection.
Replace igniter assembly if the plug is worn or damaged.
Replace the gas control valve/thermostat if socket is worn
or damaged.
5 Replace igniter assembly.
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SOLUTION