A.O. Smith HW 300 Installation & Operation Manual page 54

Green LED
Flash Code
(X+Y)
a
OFF No "Call for Heat"
Flash Fast Startup - Flame sense calibration
Heartbeat Normal operation
Recycle
3
- Flame failed during run
4 Flame sensed out of sequence
7 Flame sense leakage to ground
Low secondary voltage supply-
8
(below 15.5 Vac)
Failed trial for ignition resulting in
6+2
lockout
More than 5 flame failures during run
6+3 on the same "Call for Heat" resulting
in lockout
Flame sensed out of sequence-
6+4
longer than 10 seconds
Soft lockout due to error detected
ON
during self check sequences
Flash Code Descriptions:
a
- Flash Fast: rapid blinking.
- Heartbeat: Constant 1/2 second bright 1/2 second dim cycles.
- A single flash code number signifies that the LED flashes X times at 2Hz, remains off for two seconds, and then repeats the
sequence.
- X+Y flash codes signify that the LED flashes X times at 2Hz, remains off for two seconds, flashes Y times at 2Hz, remains off for three
seconds, and then repeats the sequence.
Lockout Models B, H, D and J Only - Green LED Status Codes
Indicates
not applicable
not applicable
not applicable
Initiate new trial for ignition. Flash
code will remain through the ignition
trial until flame is proved.
If situation self corrects within 10
seconds, control returns to normal
sequence. If flame out of sequence
remains longer than 10 seconds,
control goes to Flash code 6+4 (see
below).
Control remains in wait mode. When
the fault corrects, control resumes
normal operation after a one minute
delay.
Control remains in wait mode. When
the fault corrects, control resumes
normal operation after a one minute
delay.
Remain in lockout until "Call for
Heat" is cycled.
Remain in lockout until "Call for
Heat" is cycled.
Control waits until flame is no
longer sensed and then goes to
soft lockout. Flash code continues.
Control auto resets from soft lockout
after one hour.
Control auto resets from soft lockout
after one hour.
Table 13.
Next System Action
54
Recommended Service Action
none
none
none
If system fails to light on next trial
for ignition, check gas supply,
pilot burner, flame sense wiring,
contamination of flame rod, burner
ground connection.
Check for pilot flame. Replace gas
valve if pilot flame is present. If no
pilot flame, cycle "Call for Heat." If
error repeats, replace control.
Check flame sense lead wire for
damage or shorting. Check that
flame rod is in proper position.
Check flame rod ceramic for cracks,
damage or tracking.
Check transformer and AC line for
proper input voltage to the control.
Check with full system load on the
transformer.
Check gas supply line, pilot burner,
spark and flame sense wiring, flame
rod contaminated or out of position,
burner ground connection.
Check gas supply, pilot burner, flame
sense wiring, contamination of flame
rod, burner ground connection.
Check for pilot flame. Replace gas
valve if pilot flame present. If no pilot
flame, cycle "Call for Heat." If error
repeats, replace control.
Reset by cycling "Call for Heat." If
error repeats, replace the control.