A.O. Smith HW 300 User Manual page 22

TABLE 5. CONTINUOUS RETRY MODELS C, M, E AND K ONLY - GREEN LED STATUS CODES
GREEN LED
FLASH CODE
(X+Y)
A
OFF No "Call for Heat"
Flash Fast Startup - Flame sense calibration
Heartbeat Normal operation
5 minute Retry Delay
2 • Pilot flame not detected during
trial for ignition
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)
5 minute Retry Delay
6+2 • On every third retry on the same
"Call for Heat"
On every 6th flame failure during run
6+3
on the same "Call for Heat"
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.
INDICATES
not applicable
not applicable
not applicable
Initiate new trial for ignition after
retry delay completed.
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.
Initiate new trial for ignition after
retry delay completed.
5 minute retry delay, then initiate
new trial for ignition.
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.
NEXT SYSTEM ACTION
22
RECOMMENDED SERVICE
ACTION
none
none
none
If system fails to light on next
trial for ignition check gas supply,
pilot burner, spark and flame
sense wiring, flame sensor
contaminated or out of position,
burner ground connection.
If system fails to light on next trial
for ignition, check gas supply,
pilot burner, flame sense wiring,
contamination of flame sensor,
burner ground connection.
Check for pilot flame. Replace
gas control 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 sensor is in proper position.
Check flame sensor 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 sensor
contaminated or out of position,
burner ground connection.
Check gas supply, pilot burner,
flame sense wiring, contamination
of flame sensor, burner ground
connection.
Check for pilot flame. Replace
gas control 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.